Re: [expert] possible problems with devfsd standard configuration in Mandrake 8.2

[Todd Lyons]

Robert Grasso wrote on Wed, Jul 31, 2002 at 10:30:50PM +0200 :
> 
> Many thanks for your answer. I supposed that it was about hotplug. So in
> my case (rather simple and stable home configuration) I suppose that I
> can leave /etc/rc5.d/S99devfsd stopped ?

Modify all the entries in /etc/lilo.conf:
  s/devfs=mount/devfs=nomount/
Make sure to run '/sbin/lilo' to save those changes to the MBR.
(Civileme, correct me if I'm wrong, but it's not really rewriting the
MBR, it's rewriting the boot.b, correct?)

Then disable that devfs service from starting at boot:
  chkconfig devfsd off

> Anyway, I went on with some others tests this evening : all of them have
> been unsuccessful :-(
> - I have one service that displays [  OK  ] in vc/1 very late after that
> the desktop has started; I changed /etc/init.d/functions in order to

Probably samba.  Samba has a 'sleep 60' in it at which point it HUPs the
smbd process to reread the list of available printers that cups has been
browsing for.

> display it's name along with "OK" : because, if when I restart devfsd by
> hand from within an xterm, it starts correctly, the "modprobe "
> may be related to some timing problem ? Well, the service is 'smbd -HUP'
> : are there any modules involved with smbd which could conflict with
> devfsd ?

No, not really.  What's happening is the "compatibility" mode of devfs.
devfs can make old devices that it knows about when some process tries
to access one of these old devices.  It seems like something is
accessing a device that devfs tries to load a module and fails.  When it
fails, it doesn't seem to be failing cleanly with the endresult of a
defunct modprobe process.  Boot without devfs and that problem will
most likely go away.

> - Years ago, there were conflicts if starting gpm along with the X
> server : as my problem seems to be related to the mouse, I rebooted
> without gpm : and still got modprobe 

No longer, gpm and X have been altered to work well together.

> REGISTER.*  MKOLDCOMPAT
> UNREGISTER  .*  RMOLDCOMPAT
> REGISTER.*  MKNEWCOMPAT
> UNREGISTER  .*  RMNEWCOMPAT

These are the lines that are problem causing it.  It's a catchall for
compatibility of older programs (ie most everything will expect the
first serial port to be /dev/ttyS0, so devfs makes /dev/ttyS0 be a
symlink to the devfs version /dev/tts/0)

> # Include package-generated files from /etc/devfs/conf.d
> OPTIONAL_INCLUDE   /etc/devfs/conf.d/

Great line.  It allows you to put small files in /etc/devfs/conf.d.
This means that individual packages can install small devfs
configuration files WITHOUT having to modify the /etc/devfsd.conf or
/etc/modules.devfs files.  My LT winmodem rpm does exactly this, though
I can't claim credit for it.  I just packaged someone else's work.

Blue skies...   Todd
-- 
  Todd Lyons -- MandrakeSoft, Inc.   http://www.mandrakesoft.com/
UNIX was not designed to stop you from doing stupid things, because 
  that would also stop you from doing clever things. -- Doug Gwyn
   Cooker Version mandrake-release-9.0-0.2mdk Kernel 2.4.18-21mdk



msg56698/pgp0.pgp
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Re: [expert] possible problems with devfsd standard configuration in Mandrake 8.2

[civileme]

Robert Grasso wrote:

>Hello, 
>
>I am reporting strange problems with my Mandrake 8.2 installation on my
>Intel PC - maybe the key is with devfsd (Mandrake version is
>devfsd-1.3.25-1.1mdk). I am a 10-years Unix-user, and a 2 years
>part-time Unix/Linux admin, but I really don't know devfsd. 
>
>So I have been reporting several symptoms for several weeks/months : 
>- sometimes after logging, the OS partially hangs : ps -ef does not
>complete, and I need to reboot 
>- after the second reboot, the OS always works (I mean, ps -ef displays
>completely); but always, I have 
>
>modprobe  
>
>and this modprobe is the son of devfsd (which I unfortunately don't know
>:-( 
>BTW, the previous partial ps -ef never includes this modprobe 
>
>- in /var/log/messages, I always have at boot: 
>devfsd: error calling: symlink in GLOBAL 
>devfsd[70]: error calling: "unlink" in "GLOBAL" 
>
>Finally, one strange symptom, that I did not connect to devfsd at the
>beginning : while scrolling with the wheel in galeon overloaded with
>maybe 20 or 30 tabs in 6 windows (not konqueror or netscape or else)
>regularly the session crashed, bringing me back to the login window, and
>leaving on the virtual consoles (I have only two) a white
>square/rectangle, 1 inch for each side nearly, including a fixed ugly
>cursor arrow. Gradually, I became sure that that the wheel caused the
>crash.
>Today, I crashed the session while scrolling in evolution, moving the
>wheel in evolution for the first time in the session, just the first
>step of the forward move of the wheel; I just migrated to evolution
>these days. 
>
>I spent today some time to try to go a bit deeper; I read the man pages
>of devfsd and devfsd.conf, discovered the startup of devfsd in
>/etc/rc.d/rc.sysinit and also the one in /etc/rc.d/init.d. As I did not
>understand clearly the use of the former, I removed the symlink in
>/etc/rc5.d and rebooted. 
>
>Now I seem to be able to scroll with the wheel as much as I want in
>galeon and evolution, and the scroll even seems to be very light and
>rapid. 
>
>Some more tests : devfsd, even  with the defunct modprobe, dies quietly
>with pkill devfsd : and the defunct modprobe disappears ! Then I restart
>it by hand (/sbin/devfsd /dev) and rerun /etc/rc.d/init.d/devfsd start
>by hand : no modprobe defuncts !!! I don't understand ...
>As devfsd is S99devfsd in /etc/rc5.d with some others (linuxconf,
>medusa, local), I renumbered these so that devfsd is really the last one
>: no use, I still got modprobe  ...
>
>Unfortunately, I did not see anything useful in the logs (/var/log).
>
>I browsed in Google, but I did not see anyone with my problem. 
>Does somebody have an idea ? 
>
>I am pasting at the end my devfsd.conf : I commented in several USB
>lines (what tool generated them ???) so it's now identical to the
>original one from the rpm (excepted some spaces here and there)
>
>Best regards 
>
>
>
>
>Want to buy your Pack or Services from MandrakeSoft? 
>Go to http://www.mandrakestore.com
>
devfsd is still very much bleeding edge...  Maybe this next go-round the 
tide will turn, but someone has to get it tested and working because

There are USB memories (storage devices) and CDRWs and webcams and 
scanners and mice that regularly get plugged in or removed in a hotswap 
fashion.  hotplug is part of the answer, but devices have to ne made and 
removed dynamically as well and that is the function of devfs.  There 
are firewire hard drives that will soon need support, too.

And all of that "fluff" to some of us is still vital to many users, and 
it isn't all fluff, either.  If you want to build in a failover 
capability, then the system has to be able to handle the hotswap of 
drives, so even entry into mid-level servers is partially dependent on 
devfs.

OK, for the rest of it, I have no idea...  I am not able to reproduce 
the messages or behavior on any of my 8.2 machines, so it is a good 
question.  I have the following:

1.  Intel BP810 Chipset Celeron 466 128M 10G CDROM floppy, USB mouse and 
keyboard (Yep a logo-removed barbie(tm))
2.  ASUS A7N266-VM Duron 1G 512M DDR 40G & 20G (RAIDed with dual-boot 
fior win) PS/2 Kbd USB Optical wheelmouse CDRW/DVD
3.  Jetway 630TCF with 900MHz C3 192M SDRAM 20G Acer CDRW USB Optical 
wheelmouse PS/2 kbd
4.  ECS K7S5A Voodoo5 5500 800MHz T-Bird 256M SDRAM PS/2 Optical 
Wheelmouse and Kbd, CDRW
5.  Compaq Professional Workstation 5000 Twin 200MHz PPro 512K cache 
matched step 160M RAM PS/2 Optical wheelmouse PS/2 Kbd, NEC PD drive, 2G 
& 4G SCSI-UW drives.
6.  ECS P6VEM C3 733 256M PS/2 Mouse and Kbd 40G, LS120, CD
7.  IBM PC300GL PII-300 192MRAM 12G Wearnes CDRW PS/2 Optical 
Wheelmouse, PS/2 Kbd  Intel LX type chipset with embedded CL video on 
mainboard.


Civileme

And if you would care to actually paste devfsd.conf this time around, I 
will read it with interest





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