[beagleboard] no power on Beaglebone Black Rev C

[Saurabh Shandilya]

Hey All,

I purchased recently 7 beaglebone Black Revision C.  I have been working
with older ones for more than an year now.
But this time when I plugged USB cable from laptop and 5V DC adaptor both,
then all of a sudden it stopped working.
And now none of the 3 are working.  I am startled why it happened.  If
anyone of you people can help me out here about the problem.
Now when I insert the USB cable, the power LED glows once and then nothing
happens.  This is the case with all three of the bealgebones.
My guess - the power management/regulator  IC is doing something because
the LED glows once.
Kindly help me out here.

-- 
Regards,
saurabh shandilya
www.embedded4fun.com
+91 9910118292

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[beagleboard] How to change screen resolution in Kernel source? (Android 4.2.2 JB on BBB, OS Provider -> TI)

[호성손]

Hello.

I wanna use my 7inc hdmi touch screen

but my board's screen resolution is not fine.

i did search and find one solution : Change kernel of your OS

but i don't know *WHERE* and *HOW* can i change...

i read All guides on TI page. but there is no solution what i need

plz let me know where and how to change.

thank you.

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[beagleboard] Re: How can i change screen resolution?

[호성손]

On Thursday, July 2, 2015 at 1:45:03 AM UTC+9, LW wrote:
>
> Have you read this link, which covers almost all the information you need:
>
> http://downloads.ti.com/sitara_android/esd/TI_Android_DevKit/TI_Android_JB_4_2_2_DevKit_4_1_1/index_FDS.html
>
> And on how to setup and build the Android JB4.2.2 (Developer Guide link 
> from the linked page above):
>
> http://processors.wiki.ti.com/index.php/TI-Android-JB-4.2.2-DevKit-4.1.1_DeveloperGuide
>
> Good luck!
>
>
> On Wednesday, July 1, 2015 at 10:17:44 AM UTC-4, 호성손 wrote:
>>
>> Thank you.
>>
>> I can change my kernel source. but i don't know how to config - make 
>> uImage. and where kernel source is.
>>
>> I did google but i couldn't find...
>>
>> could you let me know how to do and where can i clone the source?
>>
>

I can build and flash uImage but how can i modify kernel source to change 
my resolution..?

i saw  source what you post but i don't know how to modify

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Re: [beagleboard] BBB SD card Debian 8.1 console image (29-06-15) will not start RNDIS, but lxqt image will

[drhunter95]

Robert,
I now have the console image working with usb over ethernet with both Linux 
and Windows PCs.

The change I had to make was to remove udhcpd and its conf files and then 
install dnsmasq

#apt-get remove udhcpd
#rm /etc/default/udhcp*
#apt-get install dnsmasq

#reboot

This change then makes /opt/scripts/boot/autoconfigure_usb0.sh in the 
console image follow same path as LXQT image.

Thanks,
Iain 





On Thursday, July 2, 2015 00:05:37 UTC + 1 William Hermans wrote:
>
> apt-get install sysv && apt-get remove --purge systemd)
>
> Or just wait for them to iron it out hehe. , .yeah.
>
> On Wed, July 1, 2015 at 2:31 PM, Robert Nelson < robert ... @ gmail.com 
>  > wrote:
>
>> On Wed, July 1, 2015 at 4:28 PM, William Hermans < yyr ... @ gmail.com 
>>  > wrote: 
>> > No way to force g_ether to ethx DEPENDING ON Whether Ethernet is 
>> connected 
>> > or not? ? Hack
>>
>>  Nope, that's debian's systemd in stretch / testing (9) .. systemd 
>> (220-7) unstable; urgency = medium   [Martin Pitt]   * Switch to 
>> net.ifnames persistant Network Interfaces (on new installations / 
>> for new hardware), and deprecate the old "Proposal: enable stateless 
>> persistant network interface names" https://lists.debian.org/ 
>> debian-devel 
>> / 2015/05 / msg00170. 
>> html 
>> 
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>  
>>
>> Regards, - Robert Nelson https://rcn-ee.com/ - For more options, visit 
>> http://beagleboard.org/discuss --- You received this message Because You 
>> are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe 
>> from this group and stop receiving emails from it, send an email to 
>> BeagleBoard 
>> ... @ googlegroups.com  . For more options, 
>> visit https://groups.google.com/d/ 
>> OptOut  .
>>
>>
>>
>>  
>>
>>
>> 
>>
>>
>> 
>> 
>>
>
>

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Re: [beagleboard] C Code to Access GPIOs-Getting permission denied when using open() to access /sys/class/gpio/export

[Brendan Merna]

Thanks! That makes a lot of sense now. I figured out I have to open export 
as write only which agrees with the permissions you showed. I've moved 
GPIOs to export while the board was running using the command line, so I 
think its okay.

So changing my code subsituting O_WRONLY for O_RDWR and now I'm getting the 
error "Writing Error: Device or Resource is busy." It doesn't seem like I 
can use C code to bring a GPIO to the user space. Is there a way around it?

I'll look up the process forking too.

On Wednesday, July 1, 2015 at 5:22:01 PM UTC-4, William Hermans wrote:
>
> Also, as I'm unsure what exporting a pin config will do while the system 
> is running . . . you should make 100% absolutely sure you know what you're 
> doing. So you do not fry your board.
>
> On Wed, Jul 1, 2015 at 2:19 PM, William Hermans  > wrote:
>
>> debian@beaglebone:~$ *cat /sys/class/gpio/export*
>> cat: /sys/class/gpio/export: *Permission denied*
>> debian@beaglebone:~$ sudo *cat /sys/class/gpio/export*
>> cat: /sys/class/gpio/export: *Permission denied*
>> debian@beaglebone:~$ *sudo su*
>> root@beaglebone:/home/debian# *cat /sys/class/gpio/export*
>> cat: /sys/class/gpio/export: *Permission denied*
>> root@beaglebone:/home/debian# *ls -al /sys/class/gpio/*
>> total 0
>> drwxr-xr-x  2 root root0 Dec 31  1999 .
>> drwxr-xr-x 59 root root0 Dec 31  1999 ..
>> *--w---  *1 root root 4096 Dec 31  1999 export
>> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip0 -> 
>> ../../devices/virtual/gpio/gpiochip0
>> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip32 -> 
>> ../../devices/virtual/gpio/gpiochip32
>> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip64 -> 
>> ../../devices/virtual/gpio/gpiochip64
>> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip96 -> 
>> ../../devices/virtual/gpio/gpiochip96
>> --w---  1 root root 4096 Dec 31  1999 unexport
>> root@beaglebone:/home/debian# *whoami*
>> root
>>
>> read this post . . 
>>
>>
>> http://unix.stackexchange.com/questions/118716/unable-to-write-to-a-gpio-pin-despite-file-permissions-on-sys-class-gpio-gpio18
>>
>> 3rd post or second answer should fix you up. However do note that what 
>> you're trying to do is "wrong". Meaning: it is insecure. You ( and I too ) 
>> need to read up on process forking. IN short, and perhaps somewhat 
>> incorrect( as I'm not 100% up to speed either ) is that you fork a process, 
>> running privileged commands, and when that command is done, the privileges 
>> are done too . . .
>>
>> Anyway, probably safer to add your regular user to a group that has 
>> limited access to that file.
>>
>>
>> On Wed, Jul 1, 2015 at 8:02 AM, Brendan Merna > > wrote:
>>
>>>
>>> I'm trying to manipulate my GPIOs using C code and running into 
>>> "Permission Denied" when running my code and opening the file 
>>> /sys/class/gpio/export. I'm using nano editor, compiling on the Beaglebone 
>>> with gcc, and I'm under root user.
>>>
>>> I would like to do this, so I can set directions and values for the 
>>> GPIOs with my code. I've heard this might be a problem with user and kernel 
>>> space conflicting. I know there are library calls in python and other 
>>> languages to do this that work. Does anyone know what this problem might be 
>>> and our their alternate calls I can do in C?
>>>
>>> I tried to just include the necessary parts of the code.
>>> Code:
>>> #include
>>> static const char *GPIO_PATH = "/sys/class/gpio/export";
>>> int main(){
>>>  int file;
>>>  if ((file = open(GPIO_PATH, O_RDWR))<0){
>>>perror("GPIO: Can't open the device.");
>>>return -1;
>>>  }
>>>  return 0;
>>> }
>>>
>>> -- 
>>> For more options, visit http://beagleboard.org/discuss
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>>> an email to beagleboard...@googlegroups.com .
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>>>
>>
>>
>

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RE: [beagleboard] driving laser on beaglebone black

[William Pretty Security]

Fortunately most laser pointer are powered by 3V, so you can just use a FET and 
one of the IO ports.

If you need a schematic, just respond to this post J

 

 

From: beagleboard@googlegroups.com [mailto:beagleboard@googlegroups.com] On 
Behalf Of Kanika Saraswat
Sent: Wednesday, July 01, 2015 2:25 AM
To: beagleboard@googlegroups.com
Subject: [beagleboard] driving laser on beaglebone black

 

I have a Laser pointer with connecting wires.I want to connect it to my 
beaglebone black and use it with webcam. Please tell me how to attach it?

 

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  _  

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2015.0.6037 / Virus Database: 4365/10102 - Release Date: 06/26/15

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[beagleboard] No keyboard input in Qt Gui app without sudo

[bremenpl]

Hello there,
I am struggling with this problem for very long now, but it got really 
serious just now after I noticed that I also cannot use scripts. Here is 
the case:

I have an embedded Qt application crosscompiled that runs on BeagleBone 
Black. It works Ok, but one thing- It doesnt accept keyboard input if i 
wont run in directly on BeagleBone Black preceeding with sudo. This is a 
problem because:

   - I cannot remote debug application and use connected keyboard, as it 
   doesnt work,
   - I cannot use keyboard when the app is in rc.local file to boot at 
   startup (even though sudo is used there).

This is critical for me at the moment and I cannot find solution to the 
problem for very long. I would really apreciate all help regarding this.

My /etc/enviroment content is here:

QWS_MOUSE_PROTO=IntelliMouse:/dev/input/mouse0 
QWS_KEYBOARD=LinuxInput:/dev/input/event1 
TSLIB_CONFFILE=/etc/ts.conf 
TSLIB_PLUGINDIR=/usr/lib/ts


 

Although I have tried many different configurations for QWS_KEYBOARD. The 
keyboard I would like to use is /dev/input/event1.

Here are my persmissions: My application rights are:

-rwxrwxrwx 1 root root 353100 Mar 2 2015 OvenViewer


 

And the input device rights are:

crwxrwxrwt 1 root root 13, 65 Mar 1 21:45 event1


 

I have set the rights in a file /etc/udev/rules.d/85-pure-data.rules:

KERNEL=="event1", MODE="777"



It really seems that all persmissions have been granted and even though, the 
keyboard doesnt work with Qt app
if i wont run it with sudo directly in the BeagleBone Black command line. I 
Also dont understand why my script in
rc.local doesnt work:

sudo /home/debian/OvenViewer -qws -nomouse &
exit 0 

I have used sudo there. I would really apreciate all help with this, I am 
not able to proceed with my project with this problem existing and I think 
I have searched everywhere for the solution. I also tried with suid bit.
Please help.

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[beagleboard] Re: Remotely connect to Beagleboard

[mickeyf]

The way we do this is as follows:

The BBB is monitoring processes and sending data via json to a web server, 
where it is displayed.
The BBB is behind a firewall, so it must be the one to initiate the 
communication. The BBB ultimately is the boss here, not the server.
When there is no data coming in, the BBB just sends out a periodic json 
message to a web server  : "Got any commands for me?"
The web server responds with "Nothing at the moment" or any of a set of 
commands that are recognized by the BBB.
The BBB reports success or failure for each command it receives.
One of the possible commands it recognizes it "Start an ssh session 
(reverse tunnel) at server x on port y". This allows us to ssh into the BBB 
when something needs to be done that was not provided for in the command 
set.
There are several layers of "fail safe" built in, so that if something 
fails then the guilty subsystem, then the app itself, and if need be 
eventually the entire board may be restarted.

This may or may not work for you or be what you have in mind.

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[beagleboard] Re: no power on Beaglebone Black Rev C

[Graham]

Were the BBB plugged into anything else at the time? Did they have anything 
connected to the I/O ports?

My guess is that you have a problem in the safety ground on either the 
laptop or in the USB power supply,
or what the BBB I/O ports was connected to.  Get out your voltmeter and 
start measuring.

Either a plug wired wrong, or no safety ground present, in which case you 
can damage the BBB, if it was 
also connected to ground, or something else via the I/O.

The one blink can mean that the input voltage is too high, or the input 
voltage is too low, or the Sitara is
drawing too much current, and is permanently damaged. It means that the 
power supply chip in the 
BBB is alive, but has gone into self protect for some reason.

--- Graham

==

On Thursday, July 2, 2015 at 3:46:19 AM UTC-5, Saurabh Shandilya wrote:
>
> Hey All,
>
> I purchased recently 7 beaglebone Black Revision C.  I have been working 
> with older ones for more than an year now.  
> But this time when I plugged USB cable from laptop and 5V DC adaptor both, 
> then all of a sudden it stopped working.
> And now none of the 3 are working.  I am startled why it happened.  If 
> anyone of you people can help me out here about the problem.
> Now when I insert the USB cable, the power LED glows once and then nothing 
> happens.  This is the case with all three of the bealgebones.
> My guess - the power management/regulator  IC is doing something because 
> the LED glows once.  
> Kindly help me out here.  
>
> -- 
> Regards, 
> saurabh shandilya
> www.embedded4fun.com
> +91 9910118292
>  

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RE: [beagleboard] TFTP boot

[g4]

Hi Robert

> > #summary, simplified uEnv.txt with
> > uname_r=4.1.0-bone9
> >
> > client_ip=192.168.1.111
> > server_ip=192.168.1.115
> > gateway=192.168.1.254

Thanks again. Awesome. Those key changes certainly make a difference. It looks 
like I'm now booting via TFTP. Just in time as the Bone has eaten 2 SD cards 
already today (!). 

So there is one key point to clarify here. The build machine has NFS and TFTP 
configured to serve exactly the same layout as you'd find on an SD card. i.e. 
The disk layout is as below 

/home//bone/rootfs/
boot/
 
vmlinuz-4.1.0-bone9 
 dbts/
 
4.1.0-bone9/

 am335x-boneblack.dtb

and the root of the TFTP directory has:

server_args = /home//bone/rootfs

*but* what actually works is to have the vmlinuz and dtb files pushed up one 
level In the hierarchy like so:

/home//bone/rootfs/
 vmlinuz-4.1.0-bone9 
 dbts/
  4.1.0-bone9/

  am335x-boneblack.dtb

Verified experimentally - but this is indeed what is expected (?)

TAIA.

Jerry




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[beagleboard] Re: Lazarus Cross Compiler for BeagleBone Black- LCL building claims errors

[felipebaranao31]

you need to install the packages -lcairo, -lgmodule-2.0... and others...

El domingo, 10 de noviembre de 2013, 18:48:03 (UTC-3), RedRock escribió:
>
> I am trying to cross compile Lazarus (Free Pascal Compiler) for BeagleBone 
> Black.
>
> Basically, I followed below tutorial..
> http://wiki.lazarus.freepascal.org/Setup_Cross_Compile_For_ARM
>
> Below is my system information.
>
>
>
>
> *- Host OS: Ubuntu 13.10- binutils: 2.23- Free Pascal Compiler (FPC from 
> now on): 2.6.3- Lazarus: 1.0.7*
>
> binutils is built for arm-linux.
> binutils and FPC have been built and tested console pascal code has been 
> built with no error. *The executable binary code was moved and tested in 
> BeagleBone Black and worked fine.*
>
> Lazarus build was fine.
>
> But the problem is about *LCL and Package Registration*.
>
> Profile to Build: *Clean Up +  Build all*
> LCL widget type: *gtk 2*
> Target OS:* Linux*
> Target CPU: *arm*
> Options: *-XParam-linux-*
> Clean up: *Clean all*
>
> But the compilation claims errors as below.
>
> Compiling resource /home/theuser/.lazarus/units/arm-linux/gtk2/lazarus.or
> Linking /home/theuser/.lazarus/bin/arm-linux/lazarus
> /usr/local/bin/arm-linux-ld: cannot find -lpthread
> /usr/local/bin/arm-linux-ld: cannot find -ldl
> /usr/local/bin/arm-linux-ld: cannot find -lX11
> /usr/local/bin/arm-linux-ld: cannot find -lgdk_pixbuf-2.0
> /usr/local/bin/arm-linux-ld: cannot find -lgtk-x11-2.0
> /usr/local/bin/arm-linux-ld: cannot find -lgdk-x11-2.0
> /usr/local/bin/arm-linux-ld: cannot find -lgobject-2.0
> /usr/local/bin/arm-linux-ld: cannot find -lglib-2.0
> /usr/local/bin/arm-linux-ld: cannot find -lgthread-2.0
> /usr/local/bin/arm-linux-ld: cannot find -lgmodule-2.0
> /usr/local/bin/arm-linux-ld: cannot find -lpango-1.0
> /usr/local/bin/arm-linux-ld: cannot find -lcairo
> /usr/local/bin/arm-linux-ld: cannot find -latk-1.0
> /usr/local/bin/arm-linux-ld: cannot find -lc
> lazarus.pp(129,42) Error: Error while linking
> lazarus.pp(129,42) Fatal: There were 1 errors compiling module, stopping
> TMessagesView.CollectLineParts WARNING: 614<>599 
> SrcLine=lazarus.pp(129,42) Fatal: There were 1 errors compiling module, 
> stopping
> TExternalToolList.Run Exception: 
> /home/theuser/lazarus/ide/lazarus.pp(129,42) Fatal: There were 1 errors 
> compiling module, stopping
> TMainIDE.DoOpenEditorFile Fixing file name: /home/theuser/lazarus/ide/ -> 
> /home/theuser/lazarus/ide
> TMainIDE.DoOpenEditorFile skipping directory /home/theuser/lazarus/ide
> TBuildManager.SetBuildTargetIDE OS=Linux CPU=arm WS=gtk2
> [WARNING] 
> (../../../lib/unity-gtk-action-group.c:1030):unity_gtk_action_group_disconnect_shell:
>  
> runtime check failed: (shell->action_group == group)
>
> *For the link error, I copied and moved library files from /lib and 
> /usr/lib of BeagleBone Black to host Ubuntu*.
>
> I searched web, but I couldn't find the reason. Please help me.
>

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[beagleboard] Enabling UART in Kernel v 4.1

[Leo Neumeyer]

I recently upgraded to Arch Linux Kernel v 4.1 and I'm trying to enable the 
UARTs. Tried the instructions for uEnv.txt but didn't work and couldn't get 
the device tree to work either. Can someone let me know how to enable the 
UART? Thanks!

-leo

 

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[beagleboard] Debugging Audio Cape configuration

[jrblack]

I don't have an Audio Cape (everywhere is out of stock) but I just want to 
test the set up as if I did.

I ran all steps as given by the instructions 
(http://elinux.org/CircuitCo:Audio_Cape_RevB) including installing a new DT 
overlay,
disabling HDMI and adding to the slots file.

Then I try speaker-test -D default:EVM and put an oscilloscope on pin 
P9_28.  No waveform comes out.  This should be the I2S serial output, but 
it's just a flat line.  I have no idea how to debug this.

Any suggestions?


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[beagleboard] point gray flycapture camera is not working with beaglebone black

[dthepok]

hi all,
i have developed point gray flycapture camera preview application in qt5. 
it is working in ubuntu. but it is not working on beaglebone black giving 
error that :
*grab loop has an error : Isochronous image transfer is not started. *
since the camera preview application from its sdk is working fine 
(developed on glade) along with the error.

what should i do?

thanks!!

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[beagleboard] Unable to get DT overlay to drive I2S pin

[jrblack]

I'm sincerely sorry if this is a dupe, but I cannot find the note I 
intended to post an hour ago...

I have followed the instructions 
here: http://elinux.org/CircuitCo:Audio_Cape_RevB

I compiled the given dts file to obtain the dtbo.  I have disabled HDMI 
(and HDMIN).  And I've added the new device:

 0: 54:PF--- 

 1: 55:PF--- 

 2: 56:PF--- 

 3: 57:PF--- 

 4: ff:P-O-L Bone-LT-eMMC-2G,00A0,Texas Instrument,BB-BONE-EMMC-2G

 5: ff:P-O-- Bone-Black-HDMI,00A0,Texas Instrument,BB-BONELT-HDMI

 6: ff:P-O-- Bone-Black-HDMIN,00A0,Texas Instrument,BB-BONELT-HDMIN

 7: ff:P-O-L Override Board Name,00A0,Override Manuf,BB-BONE-AUDI-02


I do not have an Audio Cape (they're sold out everywhere) but a scope on 
P9_28 is a flat line when I push sound out:


$ ./pcm -D default:EVM


(pcm is the sine-wave generator in the alsa examples list, and it plays a 
tone just fine out the USB port with a Turtle Beach Amigo II USB adaptor)


However, P9_25 does go from a sine wave when not running the above pcm 
program, to another sawtooth/sine wave half that frequency when I do run 
it.  None of the other pins (28, 29, 31) show any life.  I have no idea 
what's going on nor how to approach debugging this.


Linux beaglebone 3.8.13-bone47 #1 SMP Fri Apr 11 01:36:09 UTC 2014 armv7l 
GNU/Linux


BBB Rev C


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Re: [beagleboard] BBB SD card Debian 8.1 console image (29-06-15) will not start RNDIS, but lxqt image will

[Iain Hunter]

Robert,
A further update. I can now get the udhcpd implementation to work on
console image by applying a patch to
/opt/scripts/boot/autoconfigure_usb.sh. Patch is simply to use standard
location for updated udhcpd.conf rather than a /tmp one.

I'm assuming there was a reason that this was done. I found it when I
realised that https://
raw.github.com/RobertCNelson/tools/master/scripts/beaglebone-black-g-ether-load.sh
worked.
Iain

On 2 July 2015 at 11:50,  wrote:

> Robert,
> I now have the console image working with usb over ethernet with both
> Linux and Windows PCs.
>
> The change I had to make was to remove udhcpd and its conf files and then
> install dnsmasq
>
> #apt-get remove udhcpd
> #rm /etc/default/udhcp*
> #apt-get install dnsmasq
>
> #reboot
>
> This change then makes /opt/scripts/boot/autoconfigure_usb0.sh in the
> console image follow same path as LXQT image.
>
> Thanks,
> Iain
>
>
>
>
>
> On Thursday, July 2, 2015 00:05:37 UTC + 1 William Hermans wrote:
>>
>> apt-get install sysv && apt-get remove --purge systemd)
>>
>> Or just wait for them to iron it out hehe. , .yeah.
>>
>> On Wed, July 1, 2015 at 2:31 PM, Robert Nelson < robert ... @ gmail.com >
>> wrote:
>>
>>> On Wed, July 1, 2015 at 4:28 PM, William Hermans < yyr ... @ gmail.com
>>> > wrote:
>>> > No way to force g_ether to ethx DEPENDING ON Whether Ethernet is
>>> connected
>>> > or not? ? Hack
>>>
>>>  Nope, that's debian's systemd in stretch / testing (9) .. systemd
>>> (220-7) unstable; urgency = medium   [Martin Pitt]   * Switch to
>>> net.ifnames persistant Network Interfaces (on new installations /
>>> for new hardware), and deprecate the old "Proposal: enable stateless
>>> persistant network interface names" https://lists.debian.org/
>>> debian-devel
>>> / 2015/05 / msg00170.
>>> html
>>> 
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>  
>>>
>>> Regards, - Robert Nelson https://rcn-ee.com/ - For more options, visit
>>> http://beagleboard.org/discuss --- You received this message Because
>>> You are subscribed to the Google Groups "BeagleBoard" group. To
>>> unsubscribe from this group and stop receiving emails from it, send an
>>> email to BeagleBoard ... @ googlegroups.com . For more options, visit 
>>> https://groups.google.com/d/
>>> OptOut
>>>  .
>>>
>>>
>>>
>>>  
>>>
>>>
>>> 
>>>
>>>
>>>
>>> 
>>>
>>
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From 25aca78652ff48831516cebb7adea39f71d95974 Mon Sep 17 00:00:00 2001
From: Iain Hunter 
Date: Thu, 2 Jul 2015 14:44:08 +0100
Subject: [PATCH] use standard location for udhcpd.conf

---
 boot/autoconfigure_usb0.sh |4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/boot/autoconfigure_usb0.sh b/boot/autoconfigure_usb0.sh
index 8aea71b..2e106d2 100755
--- a/boot/autoconfigure_usb0.sh
+++ b/boot/autoconfigure_usb0.sh
@@ -48,9 +48,9 @@ unset deb_etc_dir \
 # Separated /etc variable to ease test on host system (by changing
 # etc_dir during test).
 deb_etc_dir=/etc
-deb_ro_dir=$(mktemp -d)
+#deb_ro_dir=$(mktemp -d)
 
-deb_udhcpd_conf=${deb_ro_dir}/udhcpd.conf
+deb_udhcpd_conf=${deb_etc_dir}/udhcpd.conf
 deb_udhcpd_default=${deb_etc_dir}/default/udhcpd
 
 deb_generated_dnsmasq_file=usb0-dhcp
-- 
1.7.9.5

Re: [beagleboard] C Code to Access GPIOs-Getting permission denied when using open() to access /sys/class/gpio/export

[William Hermans]

root@beaglebone:/home/debian# *echo 0 > /sys/class/gpio/export*
root@beaglebone:/home/debian# l*s /sys/class/gpio/*
export  gpio0  gpiochip0  gpiochip32  gpiochip64  gpiochip96  unexport
root@beaglebone:/home/debian# *echo 0 > /sys/class/gpio/unexport*
root@beaglebone:/home/debian# *ls /sys/class/gpio/*
export  gpiochip0  gpiochip32  gpiochip64  gpiochip96  unexport


So . . .write only.Here is a decent read on the subject.
http://falsinsoft.blogspot.com/2012/11/access-gpio-from-linux-user-space.html

On Thu, Jul 2, 2015 at 4:50 AM, Brendan Merna  wrote:

> Thanks! That makes a lot of sense now. I figured out I have to open export
> as write only which agrees with the permissions you showed. I've moved
> GPIOs to export while the board was running using the command line, so I
> think its okay.
>
> So changing my code subsituting O_WRONLY for O_RDWR and now I'm getting
> the error "Writing Error: Device or Resource is busy." It doesn't seem like
> I can use C code to bring a GPIO to the user space. Is there a way around
> it?
>
> I'll look up the process forking too.
>
> On Wednesday, July 1, 2015 at 5:22:01 PM UTC-4, William Hermans wrote:
>>
>> Also, as I'm unsure what exporting a pin config will do while the system
>> is running . . . you should make 100% absolutely sure you know what you're
>> doing. So you do not fry your board.
>>
>> On Wed, Jul 1, 2015 at 2:19 PM, William Hermans  wrote:
>>
>>> debian@beaglebone:~$ *cat /sys/class/gpio/export*
>>> cat: /sys/class/gpio/export: *Permission denied*
>>> debian@beaglebone:~$ sudo *cat /sys/class/gpio/export*
>>> cat: /sys/class/gpio/export: *Permission denied*
>>> debian@beaglebone:~$ *sudo su*
>>> root@beaglebone:/home/debian# *cat /sys/class/gpio/export*
>>> cat: /sys/class/gpio/export: *Permission denied*
>>> root@beaglebone:/home/debian# *ls -al /sys/class/gpio/*
>>> total 0
>>> drwxr-xr-x  2 root root0 Dec 31  1999 .
>>> drwxr-xr-x 59 root root0 Dec 31  1999 ..
>>> *--w---  *1 root root 4096 Dec 31  1999 export
>>> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip0 ->
>>> ../../devices/virtual/gpio/gpiochip0
>>> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip32 ->
>>> ../../devices/virtual/gpio/gpiochip32
>>> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip64 ->
>>> ../../devices/virtual/gpio/gpiochip64
>>> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip96 ->
>>> ../../devices/virtual/gpio/gpiochip96
>>> --w---  1 root root 4096 Dec 31  1999 unexport
>>> root@beaglebone:/home/debian# *whoami*
>>> root
>>>
>>> read this post . .
>>>
>>>
>>> http://unix.stackexchange.com/questions/118716/unable-to-write-to-a-gpio-pin-despite-file-permissions-on-sys-class-gpio-gpio18
>>>
>>> 3rd post or second answer should fix you up. However do note that what
>>> you're trying to do is "wrong". Meaning: it is insecure. You ( and I too )
>>> need to read up on process forking. IN short, and perhaps somewhat
>>> incorrect( as I'm not 100% up to speed either ) is that you fork a process,
>>> running privileged commands, and when that command is done, the privileges
>>> are done too . . .
>>>
>>> Anyway, probably safer to add your regular user to a group that has
>>> limited access to that file.
>>>
>>>
>>> On Wed, Jul 1, 2015 at 8:02 AM, Brendan Merna  wrote:
>>>

 I'm trying to manipulate my GPIOs using C code and running into
 "Permission Denied" when running my code and opening the file
 /sys/class/gpio/export. I'm using nano editor, compiling on the Beaglebone
 with gcc, and I'm under root user.

 I would like to do this, so I can set directions and values for the
 GPIOs with my code. I've heard this might be a problem with user and kernel
 space conflicting. I know there are library calls in python and other
 languages to do this that work. Does anyone know what this problem might be
 and our their alternate calls I can do in C?

 I tried to just include the necessary parts of the code.
 Code:
 #include
 static const char *GPIO_PATH = "/sys/class/gpio/export";
 int main(){
  int file;
  if ((file = open(GPIO_PATH, O_RDWR))<0){
perror("GPIO: Can't open the device.");
return -1;
  }
  return 0;
 }

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>>>
>>>
>>  --
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Re: [beagleboard] C Code to Access GPIOs-Getting permission denied when using open() to access /sys/class/gpio/export

[William Hermans]

DO also keep in mind that /sys/ is a pseudo file system. SO does not always
play by the same rules as disk based file systems.

On Thu, Jul 2, 2015 at 8:50 AM, William Hermans  wrote:

>
> root@beaglebone:/home/debian# *echo 0 > /sys/class/gpio/export*
> root@beaglebone:/home/debian# l*s /sys/class/gpio/*
> export  gpio0  gpiochip0  gpiochip32  gpiochip64  gpiochip96  unexport
> root@beaglebone:/home/debian# *echo 0 > /sys/class/gpio/unexport*
> root@beaglebone:/home/debian# *ls /sys/class/gpio/*
> export  gpiochip0  gpiochip32  gpiochip64  gpiochip96  unexport
>
>
> So . . .write only.Here is a decent read on the subject.
> http://falsinsoft.blogspot.com/2012/11/access-gpio-from-linux-user-space.html
>
> On Thu, Jul 2, 2015 at 4:50 AM, Brendan Merna  wrote:
>
>> Thanks! That makes a lot of sense now. I figured out I have to open
>> export as write only which agrees with the permissions you showed. I've
>> moved GPIOs to export while the board was running using the command line,
>> so I think its okay.
>>
>> So changing my code subsituting O_WRONLY for O_RDWR and now I'm getting
>> the error "Writing Error: Device or Resource is busy." It doesn't seem like
>> I can use C code to bring a GPIO to the user space. Is there a way around
>> it?
>>
>> I'll look up the process forking too.
>>
>> On Wednesday, July 1, 2015 at 5:22:01 PM UTC-4, William Hermans wrote:
>>>
>>> Also, as I'm unsure what exporting a pin config will do while the system
>>> is running . . . you should make 100% absolutely sure you know what you're
>>> doing. So you do not fry your board.
>>>
>>> On Wed, Jul 1, 2015 at 2:19 PM, William Hermans 
>>> wrote:
>>>
 debian@beaglebone:~$ *cat /sys/class/gpio/export*
 cat: /sys/class/gpio/export: *Permission denied*
 debian@beaglebone:~$ sudo *cat /sys/class/gpio/export*
 cat: /sys/class/gpio/export: *Permission denied*
 debian@beaglebone:~$ *sudo su*
 root@beaglebone:/home/debian# *cat /sys/class/gpio/export*
 cat: /sys/class/gpio/export: *Permission denied*
 root@beaglebone:/home/debian# *ls -al /sys/class/gpio/*
 total 0
 drwxr-xr-x  2 root root0 Dec 31  1999 .
 drwxr-xr-x 59 root root0 Dec 31  1999 ..
 *--w---  *1 root root 4096 Dec 31  1999 export
 lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip0 ->
 ../../devices/virtual/gpio/gpiochip0
 lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip32 ->
 ../../devices/virtual/gpio/gpiochip32
 lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip64 ->
 ../../devices/virtual/gpio/gpiochip64
 lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip96 ->
 ../../devices/virtual/gpio/gpiochip96
 --w---  1 root root 4096 Dec 31  1999 unexport
 root@beaglebone:/home/debian# *whoami*
 root

 read this post . .


 http://unix.stackexchange.com/questions/118716/unable-to-write-to-a-gpio-pin-despite-file-permissions-on-sys-class-gpio-gpio18

 3rd post or second answer should fix you up. However do note that what
 you're trying to do is "wrong". Meaning: it is insecure. You ( and I too )
 need to read up on process forking. IN short, and perhaps somewhat
 incorrect( as I'm not 100% up to speed either ) is that you fork a process,
 running privileged commands, and when that command is done, the privileges
 are done too . . .

 Anyway, probably safer to add your regular user to a group that has
 limited access to that file.


 On Wed, Jul 1, 2015 at 8:02 AM, Brendan Merna 
 wrote:

>
> I'm trying to manipulate my GPIOs using C code and running into
> "Permission Denied" when running my code and opening the file
> /sys/class/gpio/export. I'm using nano editor, compiling on the Beaglebone
> with gcc, and I'm under root user.
>
> I would like to do this, so I can set directions and values for the
> GPIOs with my code. I've heard this might be a problem with user and 
> kernel
> space conflicting. I know there are library calls in python and other
> languages to do this that work. Does anyone know what this problem might 
> be
> and our their alternate calls I can do in C?
>
> I tried to just include the necessary parts of the code.
> Code:
> #include
> static const char *GPIO_PATH = "/sys/class/gpio/export";
> int main(){
>  int file;
>  if ((file = open(GPIO_PATH, O_RDWR))<0){
>perror("GPIO: Can't open the device.");
>return -1;
>  }
>  return 0;
> }
>
> --
> For more options, visit http://beagleboard.org/discuss
> ---
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>


>>>  

[beagleboard] and now for NFS :)

[g4]

OK, the saga continues. We are getting close here, I am sure. I am getting a
TFTP boot and a NFS root file system.

 

One serious issue J I cannot log in! Both debian and root users fail. The
rfs is debain Jessie and I've cleared any root password stuff from
/etc/shadow

 

jevans@nfshost# cat bone/rootfs/etc/shadow

root::16595:0:9:7::: 

debian::16595:0:9:7:::

 

Any ideas?

 

FWIW Mounting the file system from the flasher image worked immediately once
nfs-common was installed.

 

uname -a

Linux beaglebone 3.8.13-bone70 #1 SMP Fri Jan 23 02:15:42 UTC 2015 armv7l
GNU/Linux

 

# attempt to mount the exported NFS rfs to check it works

root@beaglebone:~# ls -als /mnt/nfs

total 8

4 drwxr-xr-x 2 root root 4096 Mar  1 21:28 .

4 drwxr-xr-x 3 root root 4096 Mar  1 21:28 ..

# check what is exported from the main workstation

root@beaglebone:~# showmount -e debi7

Export list for debi7:

/home/jevans/bone/rootfs *

# now mount the drive

root@beaglebone:~# mount -t nfs debi7:/home/jevans/bone/rootfs /mnt/nfs

# and get a listing. All looks good

root@beaglebone:~# ls /mnt/nfs

am335x-boneblack.dtb  dtbs  media  root  sys   var

bin   etc   mntrun   tmp   vmlinuz-4.1.0-bone9

boot  home  optsbin  uEnv.txt

dev   lib   proc   srv   usr

 

Board also automounts exported NFS drive if added to etc/fstab thus:

 

UUID=ab728192-ba33-4dfb-b3ef-ae05824502c8  /  ext4
noatime,errors=remount-ro  0  1

debugfs  /sys/kernel/debug  debugfs  defaults  0  0

192.168.1.115:/home/jevans/bone/rootfs /mnt/nfs nfs defaults 0 0

 

 

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[beagleboard] Acess to Scratchpad

[Carlos Novaes]

Hello everyone.

I am facing a problem to use scratchpad to share data between PRU0 and PRU1.
On PRU1 I got:

*MOV R10, 1*
*XOUT 10, R10, 4*
*// some code that will trigger PRU0*
*// some other code to wait for PRU0 return signal*
*XIN 10, R20, 4*
*// some code to send R20 to shared data ram*
*HALT*

On PRU0 I got
*//Some code to wait signal from PRU1*
*MOV R10, 12321*
*XOUT 10, R10, 4*
*// some code to signal PRU0 we are finished*
*HALT*

In the ARM side, I can read the shared data ram but it contents is always 
1. This means that PRU0 is not updating the scratchpad, as the expected 
result would be 12321. 
How am I supposed to access the scratch pad?

My specs are:
Beaglebone black REV A6A, running debian
pasm assembler... I had tried -V2 and -V3 as the default -V1 option 
complains on the XIN and XOUT instructions.


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RE: [beagleboard] Debugging Audio Cape configuration

[g4]

> I ran all steps as given by the instructions 
> (http://elinux.org/CircuitCo:Audio_Cape_RevB) including installing a new DT 
> overlay, disabling HDMI and adding to the slots file.

>Then I try speaker-test -D default:EVM and put an oscilloscope on pin 
>P9_28.  No waveform comes out.  This should be the I2S serial output, but it's 
>just a flat line.  I have no idea how  to debug this.

What do you get if you check pinctrl? Are things set up as expected?

sudo cat /sys/kernel/debug/pinctrl/44e10800.pinmux/pinmux-pins



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Re: [beagleboard] BBB SD card Debian 8.1 console image (29-06-15) will not start RNDIS, but lxqt image will

[Robert Nelson]

On Thu, Jul 2, 2015 at 9:44 AM, Iain Hunter  wrote:
> Robert,
> A further update. I can now get the udhcpd implementation to work on console
> image by applying a patch to /opt/scripts/boot/autoconfigure_usb.sh. Patch
> is simply to use standard location for updated udhcpd.conf rather than a
> /tmp one.

Thanks applied, i'll keep on debuggin the /tmp/ location for ro users,
but till then i applied your patch!

Regards,

-- 
Robert Nelson
https://rcn-ee.com/

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[beagleboard] Re: Acess to Scratchpad

[Carlos Novaes]

I found out... it seems that the entire register files (maybe r0 to r29) 
are written in the scratchpad bank and they must be read in the exact same 
position.
That is, PRU 1 is loading data in R20, so PRU0 must also store R20.

Le jeudi 2 juillet 2015 13:39:54 UTC-3, Carlos Novaes a écrit :
>
> Hello everyone.
>
> I am facing a problem to use scratchpad to share data between PRU0 and 
> PRU1.
> On PRU1 I got:
>
> *MOV R10, 1*
> *XOUT 10, R10, 4*
> *// some code that will trigger PRU0*
> *// some other code to wait for PRU0 return signal*
> *XIN 10, R20, 4*
> *// some code to send R20 to shared data ram*
> *HALT*
>
> On PRU0 I got
> *//Some code to wait signal from PRU1*
> *MOV R10, 12321*
> *XOUT 10, R10, 4*
> *// some code to signal PRU0 we are finished*
> *HALT*
>
> In the ARM side, I can read the shared data ram but it contents is always 
> 1. This means that PRU0 is not updating the scratchpad, as the expected 
> result would be 12321. 
> How am I supposed to access the scratch pad?
>
> My specs are:
> Beaglebone black REV A6A, running debian
> pasm assembler... I had tried -V2 and -V3 as the default -V1 option 
> complains on the XIN and XOUT instructions.
>
>
>

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[beagleboard] Re: Enabling UART in Kernel v 4.1

[Leo Neumeyer]

The only solution I found is to downgrade the kernel, see:

http://archlinuxarm.org/forum/viewtopic.php?f=48&t=8872

On Thursday, July 2, 2015 at 6:52:12 AM UTC-7, Leo Neumeyer wrote:
>
> I recently upgraded to Arch Linux Kernel v 4.1 and I'm trying to enable 
> the UARTs. Tried the instructions for uEnv.txt but didn't work and couldn't 
> get the device tree to work either. Can someone let me know how to enable 
> the UART? Thanks!
>
> -leo
>
>  
>

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Re: [beagleboard] Re: Enabling UART in Kernel v 4.1

[Robert Nelson]

https://github.com/beagleboard/bb.org-overlays
On Jul 2, 2015 1:01 PM, "Leo Neumeyer"  wrote:

> The only solution I found is to downgrade the kernel, see:
>
> http://archlinuxarm.org/forum/viewtopic.php?f=48&t=8872
>
> On Thursday, July 2, 2015 at 6:52:12 AM UTC-7, Leo Neumeyer wrote:
>>
>> I recently upgraded to Arch Linux Kernel v 4.1 and I'm trying to enable
>> the UARTs. Tried the instructions for uEnv.txt but didn't work and couldn't
>> get the device tree to work either. Can someone let me know how to enable
>> the UART? Thanks!
>>
>> -leo
>>
>>
>>
>  --
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Re: [beagleboard] Re: Enabling UART in Kernel v 4.1

[Leo Neumeyer]

Thank you Robert, isn't this for debian? I am using Arch.

-leo


On Thu, Jul 2, 2015 at 11:53 AM, Robert Nelson 
wrote:

> https://github.com/beagleboard/bb.org-overlays
> On Jul 2, 2015 1:01 PM, "Leo Neumeyer"  wrote:
>
>> The only solution I found is to downgrade the kernel, see:
>>
>> http://archlinuxarm.org/forum/viewtopic.php?f=48&t=8872
>>
>> On Thursday, July 2, 2015 at 6:52:12 AM UTC-7, Leo Neumeyer wrote:
>>>
>>> I recently upgraded to Arch Linux Kernel v 4.1 and I'm trying to enable
>>> the UARTs. Tried the instructions for uEnv.txt but didn't work and couldn't
>>> get the device tree to work either. Can someone let me know how to enable
>>> the UART? Thanks!
>>>
>>> -leo
>>>
>>>
>>>
>>  --
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-- 
Leo Neumeyer, @leoneu
http://www.linkedin.com/in/leoneu

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[beagleboard] Access to TrustZone

[benoit . callebaut]

Is it possible to write a bootloader that runs in the Trust Zone secure 
zone ? I want to run custom code in secure mode. 

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Re: [beagleboard] Re: Enabling UART in Kernel v 4.1

[Robert Nelson]

On Thu, Jul 2, 2015 at 1:59 PM, Leo Neumeyer  wrote:
> Thank you Robert, isn't this for debian? I am using Arch.

While correct, it's defaults to debian stuff, Arch usually add's our
bone patch, so your current kernel should meet the .config
requirements listed in the readme.md.  Then the only other Arch
userspace dependency is the updated dtc version.  (overlay-dtc.sh
script)

Regards,

-- 
Robert Nelson
https://rcn-ee.com/

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Re: [beagleboard] C Code to Access GPIOs-Getting permission denied when using open() to access /sys/class/gpio/export

[William Hermans]

Any forward traction ?

On Thu, Jul 2, 2015 at 8:51 AM, William Hermans  wrote:

> DO also keep in mind that /sys/ is a pseudo file system. SO does not
> always play by the same rules as disk based file systems.
>
> On Thu, Jul 2, 2015 at 8:50 AM, William Hermans  wrote:
>
>>
>> root@beaglebone:/home/debian# *echo 0 > /sys/class/gpio/export*
>> root@beaglebone:/home/debian# l*s /sys/class/gpio/*
>> export  gpio0  gpiochip0  gpiochip32  gpiochip64  gpiochip96  unexport
>> root@beaglebone:/home/debian# *echo 0 > /sys/class/gpio/unexport*
>> root@beaglebone:/home/debian# *ls /sys/class/gpio/*
>> export  gpiochip0  gpiochip32  gpiochip64  gpiochip96  unexport
>>
>>
>> So . . .write only.Here is a decent read on the subject.
>> http://falsinsoft.blogspot.com/2012/11/access-gpio-from-linux-user-space.html
>>
>> On Thu, Jul 2, 2015 at 4:50 AM, Brendan Merna 
>> wrote:
>>
>>> Thanks! That makes a lot of sense now. I figured out I have to open
>>> export as write only which agrees with the permissions you showed. I've
>>> moved GPIOs to export while the board was running using the command line,
>>> so I think its okay.
>>>
>>> So changing my code subsituting O_WRONLY for O_RDWR and now I'm getting
>>> the error "Writing Error: Device or Resource is busy." It doesn't seem like
>>> I can use C code to bring a GPIO to the user space. Is there a way around
>>> it?
>>>
>>> I'll look up the process forking too.
>>>
>>> On Wednesday, July 1, 2015 at 5:22:01 PM UTC-4, William Hermans wrote:

 Also, as I'm unsure what exporting a pin config will do while the
 system is running . . . you should make 100% absolutely sure you know what
 you're doing. So you do not fry your board.

 On Wed, Jul 1, 2015 at 2:19 PM, William Hermans 
 wrote:

> debian@beaglebone:~$ *cat /sys/class/gpio/export*
> cat: /sys/class/gpio/export: *Permission denied*
> debian@beaglebone:~$ sudo *cat /sys/class/gpio/export*
> cat: /sys/class/gpio/export: *Permission denied*
> debian@beaglebone:~$ *sudo su*
> root@beaglebone:/home/debian# *cat /sys/class/gpio/export*
> cat: /sys/class/gpio/export: *Permission denied*
> root@beaglebone:/home/debian# *ls -al /sys/class/gpio/*
> total 0
> drwxr-xr-x  2 root root0 Dec 31  1999 .
> drwxr-xr-x 59 root root0 Dec 31  1999 ..
> *--w---  *1 root root 4096 Dec 31  1999 export
> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip0 ->
> ../../devices/virtual/gpio/gpiochip0
> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip32 ->
> ../../devices/virtual/gpio/gpiochip32
> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip64 ->
> ../../devices/virtual/gpio/gpiochip64
> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip96 ->
> ../../devices/virtual/gpio/gpiochip96
> --w---  1 root root 4096 Dec 31  1999 unexport
> root@beaglebone:/home/debian# *whoami*
> root
>
> read this post . .
>
>
> http://unix.stackexchange.com/questions/118716/unable-to-write-to-a-gpio-pin-despite-file-permissions-on-sys-class-gpio-gpio18
>
> 3rd post or second answer should fix you up. However do note that what
> you're trying to do is "wrong". Meaning: it is insecure. You ( and I too )
> need to read up on process forking. IN short, and perhaps somewhat
> incorrect( as I'm not 100% up to speed either ) is that you fork a 
> process,
> running privileged commands, and when that command is done, the privileges
> are done too . . .
>
> Anyway, probably safer to add your regular user to a group that has
> limited access to that file.
>
>
> On Wed, Jul 1, 2015 at 8:02 AM, Brendan Merna 
> wrote:
>
>>
>> I'm trying to manipulate my GPIOs using C code and running into
>> "Permission Denied" when running my code and opening the file
>> /sys/class/gpio/export. I'm using nano editor, compiling on the 
>> Beaglebone
>> with gcc, and I'm under root user.
>>
>> I would like to do this, so I can set directions and values for the
>> GPIOs with my code. I've heard this might be a problem with user and 
>> kernel
>> space conflicting. I know there are library calls in python and other
>> languages to do this that work. Does anyone know what this problem might 
>> be
>> and our their alternate calls I can do in C?
>>
>> I tried to just include the necessary parts of the code.
>> Code:
>> #include
>> static const char *GPIO_PATH = "/sys/class/gpio/export";
>> int main(){
>>  int file;
>>  if ((file = open(GPIO_PATH, O_RDWR))<0){
>>perror("GPIO: Can't open the device.");
>>return -1;
>>  }
>>  return 0;
>> }
>>
>> --
>> For more options, visit http://beagleboard.org/discuss
>> ---
>> You received this message because you are subscribed to the Google
>> Groups "BeagleBoard" group

Re: [beagleboard] C Code to Access GPIOs-Getting permission denied when using open() to access /sys/class/gpio/export

[jrblack]

On Wednesday, July 1, 2015 at 3:19:27 PM UTC-6, William Hermans wrote:
>
> debian@beaglebone:~$ *cat /sys/class/gpio/export*
> cat: /sys/class/gpio/export: *Permission denied*
> debian@beaglebone:~$ sudo *cat /sys/class/gpio/export*
> cat: /sys/class/gpio/export: *Permission denied*
> debian@beaglebone:~$ *sudo su*
> root@beaglebone:/home/debian# *cat /sys/class/gpio/export*
> cat: /sys/class/gpio/export: *Permission denied*
> root@beaglebone:/home/debian# *ls -al /sys/class/gpio/*
> total 0
> drwxr-xr-x  2 root root0 Dec 31  1999 .
> drwxr-xr-x 59 root root0 Dec 31  1999 ..
> *--w---  *1 root root 4096 Dec 31  1999 export
> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip0 -> 
> ../../devices/virtual/gpio/gpiochip0
> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip32 -> 
> ../../devices/virtual/gpio/gpiochip32
> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip64 -> 
> ../../devices/virtual/gpio/gpiochip64
> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip96 -> 
> ../../devices/virtual/gpio/gpiochip96
> --w---  1 root root 4096 Dec 31  1999 unexport
> root@beaglebone:/home/debian# *whoami*
> root
>
> read this post . . 
>
>
> http://unix.stackexchange.com/questions/118716/unable-to-write-to-a-gpio-pin-despite-file-permissions-on-sys-class-gpio-gpio18
>
> 3rd post or second answer should fix you up. However do note that what 
> you're trying to do is "wrong". Meaning: it is insecure. You ( and I too ) 
> need to read up on process forking. IN short, and perhaps somewhat 
> incorrect( as I'm not 100% up to speed either ) is that you fork a process, 
> running privileged commands, and when that command is done, the privileges 
> are done too . . .
>
> Anyway, probably safer to add your regular user to a group that has 
> limited access to that file.
>

The spawned process inherits the real UID (and effective and saved UIDs) 
from the parent.  But here he needs root to write to the GPIO file.

This is really only a security issue if there are ever other users on the 
box.  Important security practices for a multiuser machine, yes, but for a 
BBB acting as (say) a media server with only a wired network connection, 
not really that important.

 

>
>
> On Wed, Jul 1, 2015 at 8:02 AM, Brendan Merna  > wrote:
>
>>
>> I'm trying to manipulate my GPIOs using C code and running into 
>> "Permission Denied" when running my code and opening the file 
>> /sys/class/gpio/export. I'm using nano editor, compiling on the Beaglebone 
>> with gcc, and I'm under root user.
>>
>> I would like to do this, so I can set directions and values for the GPIOs 
>> with my code. I've heard this might be a problem with user and kernel space 
>> conflicting. I know there are library calls in python and other languages 
>> to do this that work. Does anyone know what this problem might be and our 
>> their alternate calls I can do in C?
>>
>> I tried to just include the necessary parts of the code.
>> Code:
>> #include
>> static const char *GPIO_PATH = "/sys/class/gpio/export";
>> int main(){
>>  int file;
>>  if ((file = open(GPIO_PATH, O_RDWR))<0){
>>perror("GPIO: Can't open the device.");
>>return -1;
>>  }
>>  return 0;
>> }
>>
>> -- 
>> For more options, visit http://beagleboard.org/discuss
>> --- 
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>> "BeagleBoard" group.
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>> email to beagleboard...@googlegroups.com .
>> For more options, visit https://groups.google.com/d/optout.
>>
>
>

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Re: [beagleboard] C Code to Access GPIOs-Getting permission denied when using open() to access /sys/class/gpio/export

[William Hermans]

>
> *The spawned process inherits the real UID (and effective and saved UIDs)
> from the parent.  But here he needs root to write to the GPIO file.*
>
> *This is really only a security issue if there are ever other users on the
> box.  Important security practices for a multiuser machine, yes, but for a
> BBB acting as (say) a media server with only a wired network connection,
> not really that important.*
>

Fair enough. Though I tend to err on the side of caution, since *sometimes*
you never know what can come back and bite you.

By the way, that was my own file system / commands above. No idea what his
actual file system groups / permissions looks like.

Since you seem to be more knowledgeable on the subject. What would you
suggest that one do in this situation. Assuming the system could be multi
user, and internet facing ?

On Thu, Jul 2, 2015 at 6:17 PM,  wrote:

>
>
> On Wednesday, July 1, 2015 at 3:19:27 PM UTC-6, William Hermans wrote:
>>
>> debian@beaglebone:~$ *cat /sys/class/gpio/export*
>> cat: /sys/class/gpio/export: *Permission denied*
>> debian@beaglebone:~$ sudo *cat /sys/class/gpio/export*
>> cat: /sys/class/gpio/export: *Permission denied*
>> debian@beaglebone:~$ *sudo su*
>> root@beaglebone:/home/debian# *cat /sys/class/gpio/export*
>> cat: /sys/class/gpio/export: *Permission denied*
>> root@beaglebone:/home/debian# *ls -al /sys/class/gpio/*
>> total 0
>> drwxr-xr-x  2 root root0 Dec 31  1999 .
>> drwxr-xr-x 59 root root0 Dec 31  1999 ..
>> *--w---  *1 root root 4096 Dec 31  1999 export
>> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip0 ->
>> ../../devices/virtual/gpio/gpiochip0
>> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip32 ->
>> ../../devices/virtual/gpio/gpiochip32
>> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip64 ->
>> ../../devices/virtual/gpio/gpiochip64
>> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip96 ->
>> ../../devices/virtual/gpio/gpiochip96
>> --w---  1 root root 4096 Dec 31  1999 unexport
>> root@beaglebone:/home/debian# *whoami*
>> root
>>
>> read this post . .
>>
>>
>> http://unix.stackexchange.com/questions/118716/unable-to-write-to-a-gpio-pin-despite-file-permissions-on-sys-class-gpio-gpio18
>>
>> 3rd post or second answer should fix you up. However do note that what
>> you're trying to do is "wrong". Meaning: it is insecure. You ( and I too )
>> need to read up on process forking. IN short, and perhaps somewhat
>> incorrect( as I'm not 100% up to speed either ) is that you fork a process,
>> running privileged commands, and when that command is done, the privileges
>> are done too . . .
>>
>> Anyway, probably safer to add your regular user to a group that has
>> limited access to that file.
>>
>
> The spawned process inherits the real UID (and effective and saved UIDs)
> from the parent.  But here he needs root to write to the GPIO file.
>
> This is really only a security issue if there are ever other users on the
> box.  Important security practices for a multiuser machine, yes, but for a
> BBB acting as (say) a media server with only a wired network connection,
> not really that important.
>
>
>
>>
>>
>> On Wed, Jul 1, 2015 at 8:02 AM, Brendan Merna  wrote:
>>
>>>
>>> I'm trying to manipulate my GPIOs using C code and running into
>>> "Permission Denied" when running my code and opening the file
>>> /sys/class/gpio/export. I'm using nano editor, compiling on the Beaglebone
>>> with gcc, and I'm under root user.
>>>
>>> I would like to do this, so I can set directions and values for the
>>> GPIOs with my code. I've heard this might be a problem with user and kernel
>>> space conflicting. I know there are library calls in python and other
>>> languages to do this that work. Does anyone know what this problem might be
>>> and our their alternate calls I can do in C?
>>>
>>> I tried to just include the necessary parts of the code.
>>> Code:
>>> #include
>>> static const char *GPIO_PATH = "/sys/class/gpio/export";
>>> int main(){
>>>  int file;
>>>  if ((file = open(GPIO_PATH, O_RDWR))<0){
>>>perror("GPIO: Can't open the device.");
>>>return -1;
>>>  }
>>>  return 0;
>>> }
>>>
>>> --
>>> For more options, visit http://beagleboard.org/discuss
>>> ---
>>> You received this message because you are subscribed to the Google
>>> Groups "BeagleBoard" group.
>>> To unsubscribe from this group and stop receiving emails from it, send
>>> an email to beagleboard...@googlegroups.com.
>>> For more options, visit https://groups.google.com/d/optout.
>>>
>>
>>  --
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[beagleboard] Ubuntu 13.04 eMMC flasher

[mmsarode]

Hi,

 I am trying to install Ubuntu 13.04 eMMC flasher image on Beaglebone 
black. However, the links for Ubuntu 13.04 eMMC flash image does not work.

Can anyone point me to a download link for the image?  Has anyone 
downloaded this image before?

Regards,
Mahesh Sarode

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[beagleboard] Debian Jessie issues?

[Adam Weiss]

I just updated to Jessie and I noticed 2 strange issues.
Wondering if anyone else has either seen these issues or knows what's up.

Once I updated, I noticed 2 things weren't working anymore:

1. USB connection to BBB doesn't work.  Windows doesn't even see it as a 
mass storage, let alone the USB network.
2. simple LED examples using bonescript via Cloud 9 don't seem to update 
the LEDs

For #1, it's not too big of a deal, since I just network in either wired or 
WiFi, but I'm still curious why that didn't work.
When I do ifconfig, I can see the USB network just fine, and it looks to be 
configured properly.
Windows detects the BBB, but can't seem to figure out a driver to use for 
it.

For #2, it might be user error.  This is the first I've tried Cloud 9 and 
bonescript, but even the built in demos don't seem to work.
It is connected to the board just fine, and when I run the demos to (for 
example) turn on USR3, everything seems to be running...just nothing 
happens on the LED.  And unfortunately, since I'm a noob, I can't figure 
out how to step through and see what's going on...I just click run, and it 
shows it running...

Thanks for any help!

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Re: [beagleboard] C Code to Access GPIOs-Getting permission denied when using open() to access /sys/class/gpio/export

[jrblack]

On Thursday, July 2, 2015 at 7:37:17 PM UTC-6, William Hermans wrote:
>
> *The spawned process inherits the real UID (and effective and saved UIDs) 
>> from the parent.  But here he needs root to write to the GPIO file.*
>>
>> *This is really only a security issue if there are ever other users on 
>> the box.  Important security practices for a multiuser machine, yes, but 
>> for a BBB acting as (say) a media server with only a wired network 
>> connection, not really that important.*
>>
>
> Fair enough. Though I tend to err on the side of caution, since 
> *sometimes* you never know what can come back and bite you. 
>
> By the way, that was my own file system / commands above. No idea what his 
> actual file system groups / permissions looks like. 
>
> Since you seem to be more knowledgeable on the subject. What would you 
> suggest that one do in this situation. Assuming the system could be multi 
> user, and internet facing ?
>
>
This is a big topic... securing an Internet-facing server requires a lot of 
training on how to write secure software, and it's easy to get it wrong 
(there are daily reports of breaches when people blow it).  I would say you 
install only well-known and well-trusted software, go for servers that are 
known to be more secure (eg, qmail instead of sendmail and djbdns instead 
of bind).  And if you're writing web apps, take a course in webapp security 
(OWASP is a good place to start).

Unrelated topic: I've tried to post my own question about the BBB here 
twice now and it says "your post will appear after it's been approved" but 
this never happens.  Is the group moderated?  When do the mods come by? 
 (Sorry to derail the thread!!)

 

> On Thu, Jul 2, 2015 at 6:17 PM, > wrote:
>
>>
>>
>> On Wednesday, July 1, 2015 at 3:19:27 PM UTC-6, William Hermans wrote:
>>>
>>> debian@beaglebone:~$ *cat /sys/class/gpio/export*
>>> cat: /sys/class/gpio/export: *Permission denied*
>>> debian@beaglebone:~$ sudo *cat /sys/class/gpio/export*
>>> cat: /sys/class/gpio/export: *Permission denied*
>>> debian@beaglebone:~$ *sudo su*
>>> root@beaglebone:/home/debian# *cat /sys/class/gpio/export*
>>> cat: /sys/class/gpio/export: *Permission denied*
>>> root@beaglebone:/home/debian# *ls -al /sys/class/gpio/*
>>> total 0
>>> drwxr-xr-x  2 root root0 Dec 31  1999 .
>>> drwxr-xr-x 59 root root0 Dec 31  1999 ..
>>> *--w---  *1 root root 4096 Dec 31  1999 export
>>> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip0 -> 
>>> ../../devices/virtual/gpio/gpiochip0
>>> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip32 -> 
>>> ../../devices/virtual/gpio/gpiochip32
>>> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip64 -> 
>>> ../../devices/virtual/gpio/gpiochip64
>>> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip96 -> 
>>> ../../devices/virtual/gpio/gpiochip96
>>> --w---  1 root root 4096 Dec 31  1999 unexport
>>> root@beaglebone:/home/debian# *whoami*
>>> root
>>>
>>> read this post . . 
>>>
>>>
>>> http://unix.stackexchange.com/questions/118716/unable-to-write-to-a-gpio-pin-despite-file-permissions-on-sys-class-gpio-gpio18
>>>
>>> 3rd post or second answer should fix you up. However do note that what 
>>> you're trying to do is "wrong". Meaning: it is insecure. You ( and I too ) 
>>> need to read up on process forking. IN short, and perhaps somewhat 
>>> incorrect( as I'm not 100% up to speed either ) is that you fork a process, 
>>> running privileged commands, and when that command is done, the privileges 
>>> are done too . . .
>>>
>>> Anyway, probably safer to add your regular user to a group that has 
>>> limited access to that file.
>>>
>>
>> The spawned process inherits the real UID (and effective and saved UIDs) 
>> from the parent.  But here he needs root to write to the GPIO file.
>>
>> This is really only a security issue if there are ever other users on the 
>> box.  Important security practices for a multiuser machine, yes, but for a 
>> BBB acting as (say) a media server with only a wired network connection, 
>> not really that important.
>>
>>  
>>
>>>
>>>
>>> On Wed, Jul 1, 2015 at 8:02 AM, Brendan Merna  wrote:
>>>

 I'm trying to manipulate my GPIOs using C code and running into 
 "Permission Denied" when running my code and opening the file 
 /sys/class/gpio/export. I'm using nano editor, compiling on the Beaglebone 
 with gcc, and I'm under root user.

 I would like to do this, so I can set directions and values for the 
 GPIOs with my code. I've heard this might be a problem with user and 
 kernel 
 space conflicting. I know there are library calls in python and other 
 languages to do this that work. Does anyone know what this problem might 
 be 
 and our their alternate calls I can do in C?

 I tried to just include the necessary parts of the code.
 Code:
 #include
 static const char *GPIO_PATH = "/sys/class/gpio/export";
 int main(){
  int file;
  if ((file = open(GPIO

Re: [beagleboard] C Code to Access GPIOs-Getting permission denied when using open() to access /sys/class/gpio/export

[William Hermans]

Gerald and maybe Jason have the power to approve new users to post. No idea
when they'll get on, but do also keep in mind it's the 4th of July weekend(
possibly already started for some ) So you may have to wait until Monday.

On Thu, Jul 2, 2015 at 8:07 PM,  wrote:

>
>
> On Thursday, July 2, 2015 at 7:37:17 PM UTC-6, William Hermans wrote:
>>
>> *The spawned process inherits the real UID (and effective and saved UIDs)
>>> from the parent.  But here he needs root to write to the GPIO file.*
>>>
>>> *This is really only a security issue if there are ever other users on
>>> the box.  Important security practices for a multiuser machine, yes, but
>>> for a BBB acting as (say) a media server with only a wired network
>>> connection, not really that important.*
>>>
>>
>> Fair enough. Though I tend to err on the side of caution, since
>> *sometimes* you never know what can come back and bite you.
>>
>> By the way, that was my own file system / commands above. No idea what
>> his actual file system groups / permissions looks like.
>>
>> Since you seem to be more knowledgeable on the subject. What would you
>> suggest that one do in this situation. Assuming the system could be multi
>> user, and internet facing ?
>>
>>
> This is a big topic... securing an Internet-facing server requires a lot
> of training on how to write secure software, and it's easy to get it wrong
> (there are daily reports of breaches when people blow it).  I would say you
> install only well-known and well-trusted software, go for servers that are
> known to be more secure (eg, qmail instead of sendmail and djbdns instead
> of bind).  And if you're writing web apps, take a course in webapp security
> (OWASP is a good place to start).
>
> Unrelated topic: I've tried to post my own question about the BBB here
> twice now and it says "your post will appear after it's been approved" but
> this never happens.  Is the group moderated?  When do the mods come by?
>  (Sorry to derail the thread!!)
>
>
>
>> On Thu, Jul 2, 2015 at 6:17 PM,  wrote:
>>
>>>
>>>
>>> On Wednesday, July 1, 2015 at 3:19:27 PM UTC-6, William Hermans wrote:

 debian@beaglebone:~$ *cat /sys/class/gpio/export*
 cat: /sys/class/gpio/export: *Permission denied*
 debian@beaglebone:~$ sudo *cat /sys/class/gpio/export*
 cat: /sys/class/gpio/export: *Permission denied*
 debian@beaglebone:~$ *sudo su*
 root@beaglebone:/home/debian# *cat /sys/class/gpio/export*
 cat: /sys/class/gpio/export: *Permission denied*
 root@beaglebone:/home/debian# *ls -al /sys/class/gpio/*
 total 0
 drwxr-xr-x  2 root root0 Dec 31  1999 .
 drwxr-xr-x 59 root root0 Dec 31  1999 ..
 *--w---  *1 root root 4096 Dec 31  1999 export
 lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip0 ->
 ../../devices/virtual/gpio/gpiochip0
 lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip32 ->
 ../../devices/virtual/gpio/gpiochip32
 lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip64 ->
 ../../devices/virtual/gpio/gpiochip64
 lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip96 ->
 ../../devices/virtual/gpio/gpiochip96
 --w---  1 root root 4096 Dec 31  1999 unexport
 root@beaglebone:/home/debian# *whoami*
 root

 read this post . .


 http://unix.stackexchange.com/questions/118716/unable-to-write-to-a-gpio-pin-despite-file-permissions-on-sys-class-gpio-gpio18

 3rd post or second answer should fix you up. However do note that what
 you're trying to do is "wrong". Meaning: it is insecure. You ( and I too )
 need to read up on process forking. IN short, and perhaps somewhat
 incorrect( as I'm not 100% up to speed either ) is that you fork a process,
 running privileged commands, and when that command is done, the privileges
 are done too . . .

 Anyway, probably safer to add your regular user to a group that has
 limited access to that file.

>>>
>>> The spawned process inherits the real UID (and effective and saved UIDs)
>>> from the parent.  But here he needs root to write to the GPIO file.
>>>
>>> This is really only a security issue if there are ever other users on
>>> the box.  Important security practices for a multiuser machine, yes, but
>>> for a BBB acting as (say) a media server with only a wired network
>>> connection, not really that important.
>>>
>>>
>>>


 On Wed, Jul 1, 2015 at 8:02 AM, Brendan Merna 
 wrote:

>
> I'm trying to manipulate my GPIOs using C code and running into
> "Permission Denied" when running my code and opening the file
> /sys/class/gpio/export. I'm using nano editor, compiling on the Beaglebone
> with gcc, and I'm under root user.
>
> I would like to do this, so I can set directions and values for the
> GPIOs with my code. I've heard this might be a problem with user and 
> kernel
> space conflicting. I know there are library calls in python and other
> lang

Re: [beagleboard] C Code to Access GPIOs-Getting permission denied when using open() to access /sys/class/gpio/export

[William Hermans]

jrblack, also, you can mail me personally, and I'll forward, or just make a
new post on your behalf. Assuming I can not answer the question myself.

On Thu, Jul 2, 2015 at 9:07 PM, William Hermans  wrote:

> Gerald and maybe Jason have the power to approve new users to post. No
> idea when they'll get on, but do also keep in mind it's the 4th of July
> weekend( possibly already started for some ) So you may have to wait until
> Monday.
>
> On Thu, Jul 2, 2015 at 8:07 PM,  wrote:
>
>>
>>
>> On Thursday, July 2, 2015 at 7:37:17 PM UTC-6, William Hermans wrote:
>>>
>>> *The spawned process inherits the real UID (and effective and saved
 UIDs) from the parent.  But here he needs root to write to the GPIO file.*

 *This is really only a security issue if there are ever other users on
 the box.  Important security practices for a multiuser machine, yes, but
 for a BBB acting as (say) a media server with only a wired network
 connection, not really that important.*

>>>
>>> Fair enough. Though I tend to err on the side of caution, since
>>> *sometimes* you never know what can come back and bite you.
>>>
>>> By the way, that was my own file system / commands above. No idea what
>>> his actual file system groups / permissions looks like.
>>>
>>> Since you seem to be more knowledgeable on the subject. What would you
>>> suggest that one do in this situation. Assuming the system could be multi
>>> user, and internet facing ?
>>>
>>>
>> This is a big topic... securing an Internet-facing server requires a lot
>> of training on how to write secure software, and it's easy to get it wrong
>> (there are daily reports of breaches when people blow it).  I would say you
>> install only well-known and well-trusted software, go for servers that are
>> known to be more secure (eg, qmail instead of sendmail and djbdns instead
>> of bind).  And if you're writing web apps, take a course in webapp security
>> (OWASP is a good place to start).
>>
>> Unrelated topic: I've tried to post my own question about the BBB here
>> twice now and it says "your post will appear after it's been approved" but
>> this never happens.  Is the group moderated?  When do the mods come by?
>>  (Sorry to derail the thread!!)
>>
>>
>>
>>> On Thu, Jul 2, 2015 at 6:17 PM,  wrote:
>>>


 On Wednesday, July 1, 2015 at 3:19:27 PM UTC-6, William Hermans wrote:
>
> debian@beaglebone:~$ *cat /sys/class/gpio/export*
> cat: /sys/class/gpio/export: *Permission denied*
> debian@beaglebone:~$ sudo *cat /sys/class/gpio/export*
> cat: /sys/class/gpio/export: *Permission denied*
> debian@beaglebone:~$ *sudo su*
> root@beaglebone:/home/debian# *cat /sys/class/gpio/export*
> cat: /sys/class/gpio/export: *Permission denied*
> root@beaglebone:/home/debian# *ls -al /sys/class/gpio/*
> total 0
> drwxr-xr-x  2 root root0 Dec 31  1999 .
> drwxr-xr-x 59 root root0 Dec 31  1999 ..
> *--w---  *1 root root 4096 Dec 31  1999 export
> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip0 ->
> ../../devices/virtual/gpio/gpiochip0
> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip32 ->
> ../../devices/virtual/gpio/gpiochip32
> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip64 ->
> ../../devices/virtual/gpio/gpiochip64
> lrwxrwxrwx  1 root root0 Dec 31  1999 gpiochip96 ->
> ../../devices/virtual/gpio/gpiochip96
> --w---  1 root root 4096 Dec 31  1999 unexport
> root@beaglebone:/home/debian# *whoami*
> root
>
> read this post . .
>
>
> http://unix.stackexchange.com/questions/118716/unable-to-write-to-a-gpio-pin-despite-file-permissions-on-sys-class-gpio-gpio18
>
> 3rd post or second answer should fix you up. However do note that what
> you're trying to do is "wrong". Meaning: it is insecure. You ( and I too )
> need to read up on process forking. IN short, and perhaps somewhat
> incorrect( as I'm not 100% up to speed either ) is that you fork a 
> process,
> running privileged commands, and when that command is done, the privileges
> are done too . . .
>
> Anyway, probably safer to add your regular user to a group that has
> limited access to that file.
>

 The spawned process inherits the real UID (and effective and saved
 UIDs) from the parent.  But here he needs root to write to the GPIO file.

 This is really only a security issue if there are ever other users on
 the box.  Important security practices for a multiuser machine, yes, but
 for a BBB acting as (say) a media server with only a wired network
 connection, not really that important.



>
>
> On Wed, Jul 1, 2015 at 8:02 AM, Brendan Merna 
> wrote:
>
>>
>> I'm trying to manipulate my GPIOs using C code and running into
>> "Permission Denied" when running my code and opening the file
>> /sys/class/gpio/export. I'm using nano edi

Re: [beagleboard] Debian Jessie issues?

[William Hermans]

#1
https://groups.google.com/forum/#!searchin/beagleboard/RNDIS|sort:date/beagleboard/T7N2xs7K0TU/u4XBZRfEVmMJ

Read the last few posts. In your case though, you *may* have to uninstall
older drivers to get g_multi or g_ether working. WIndows can be crazy that
way sometimes.

#2 I'm not sure of. However I suspect since there have been reports of
various issues with cape manager lately, and this image is pretty much a
work in progress . . . that is is related to cape manager. Don't know for
sure though.

On Thu, Jul 2, 2015 at 7:29 PM, Adam Weiss  wrote:

> I just updated to Jessie and I noticed 2 strange issues.
> Wondering if anyone else has either seen these issues or knows what's up.
>
> Once I updated, I noticed 2 things weren't working anymore:
>
> 1. USB connection to BBB doesn't work.  Windows doesn't even see it as a
> mass storage, let alone the USB network.
> 2. simple LED examples using bonescript via Cloud 9 don't seem to update
> the LEDs
>
> For #1, it's not too big of a deal, since I just network in either wired
> or WiFi, but I'm still curious why that didn't work.
> When I do ifconfig, I can see the USB network just fine, and it looks to
> be configured properly.
> Windows detects the BBB, but can't seem to figure out a driver to use for
> it.
>
> For #2, it might be user error.  This is the first I've tried Cloud 9 and
> bonescript, but even the built in demos don't seem to work.
> It is connected to the board just fine, and when I run the demos to (for
> example) turn on USR3, everything seems to be running...just nothing
> happens on the LED.  And unfortunately, since I'm a noob, I can't figure
> out how to step through and see what's going on...I just click run, and it
> shows it running...
>
> Thanks for any help!
>
> --
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Re: [beagleboard] how to use python ?? ( on BBB)

[멘지]

My kirnel bersion is 3.8.13 and I'm using Angstrom Linux 

sudo is not command in Angstrom  

how can i use python ??  LED is not working  




2015년 5월 29일 금요일 오전 2시 10분 4초 UTC+9, Miguel Aveiro 님의 말:

>  Which kernel version are you using (just type: uname -a)? 
>
> If your are using the 3.14 kernel, the GPIO.setup() don't function like it 
> was supposed to. You need to export the pin first. You should take a look 
> at config-pin from beaglebone-universal-io (
> https://github.com/cdsteinkuehler/beaglebone-universal-io).
>
> If you are using the 3.8 kernel, try running with sudo.
>
>  Miguel Zacatei Aveiro
>
> On 27-05-2015 22:09, 멘지 wrote:
>  
>  i'm Newbie in beagleboneblack
>
>  i'm use cloud9 but i want to use python  
>
>  So, I try to python tutorial  blink  LED 
>
>  
> 
>
>
>  nano blink.py   <-- command 
> just blink LED code 
>
>  
>  But , 
>
>  
> 
>
>  when i command   
>
>   -- >  python blink.py   
>
>  LED is not working   just  stop . 
>
>  Can someone help me ?? 
>
>  
>  
>  -- 
> For more options, visit http://beagleboard.org/discuss
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>
>
> 

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Re: [beagleboard] Debugging Audio Cape configuration

[jrblack]

On Thursday, July 2, 2015 at 10:55:40 AM UTC-6, J Evans wrote:
>
> > I ran all steps as given by the instructions 
> > (http://elinux.org/CircuitCo:Audio_Cape_RevB) including installing a 
> new DT overlay, disabling HDMI and adding to the slots file. 
>
> >Then I try speaker-test -D default:EVM and put an oscilloscope on pin 
> >P9_28.  No waveform comes out.  This should be the I2S serial output, but 
> it's just a flat line.  I have no idea how  to debug this. 
>
> What do you get if you check pinctrl? Are things set up as expected? 
>
> sudo cat /sys/kernel/debug/pinctrl/44e10800.pinmux/pinmux-pins 
>
>
> Seems like it:

Relevant pins:

>From dts:

pinctrl-single,pins = <

0x1ac 0x00  /* mcasp0_ahclkx,   
  MODE0 | INPUT */

0x19c 0x22  /* 
mcasp0_ahclkr, */

0x194 0x20  /* mcasp0_fsx,  
  MODE0 | OUTPUT  */

0x190 0x20  /* 
mcasp0_aclkr.mcasp0_aclkx, MODE0 | OUTPUT_PULLDOWN */

0x198 0x20

>;


>From pinmux-pins (in same order as above):

pin 107 (44e109ac): 48038000.mcasp (GPIO UNCLAIMED) function 
pinmux_bone_audio_cape_audio_pins group pinmux_bone_audio_cape_audio_pins
pin 103 (44e1099c): 48038000.mcasp (GPIO UNCLAIMED) function 
pinmux_bone_audio_cape_audio_pins group pinmux_bone_audio_cape_audio_pins
pin 101 (44e10994): 48038000.mcasp (GPIO UNCLAIMED) function 
pinmux_bone_audio_cape_audio_pins group pinmux_bone_audio_cape_audio_pins

pin 100 (44e10990): 48038000.mcasp (GPIO UNCLAIMED) function 
pinmux_bone_audio_cape_audio_pins group pinmux_bone_audio_cape_audio_pins

pin 102 (44e10998): 48038000.mcasp (GPIO UNCLAIMED) function 
pinmux_bone_audio_cape_audio_pins group pinmux_bone_audio_cape_audio_pins


And in /sys/kernel/debug/pinctrl/44e10800.pinmux/pinmux-pins all the modes 
are as they should be from the .dts, except offset 0x198 has 0x70 instead 
of the given 0x20 mode from the .dts file.


I have tried this on two separate BBB's with identical results.


root@beaglebone:~# cat /sys/devices/bone_capemgr.9/slots 

 0: 54:PF--- 

 1: 55:PF--- 

 2: 56:PF--- 

 3: 57:PF--- 

 4: ff:P-O-L Bone-LT-eMMC-2G,00A0,Texas Instrument,BB-BONE-EMMC-2G

 5: ff:P-O-- Bone-Black-HDMI,00A0,Texas Instrument,BB-BONELT-HDMI

 6: ff:P-O-- Bone-Black-HDMIN,00A0,Texas Instrument,BB-BONELT-HDMIN

 7: ff:P-O-L Override Board Name,00A0,Override Manuf,BB-BONE-AUDI-02

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