Re: usb_debug serial driver protocol

2015-01-28 Thread Peter Stuge
Greg KH wrote:
> > Is that some kind of initialization protocol I have to handle? If yes,
> > where do I find information about it?
> 
> The protocol should be part of the USB specification.

USB debug class devices use no protocol, just transfers of 1-8 bytes,
used in arbitrary ways by the various device users.


> I've found that screen can leave usb serial ports in an "odd" state,
> it's not unique to this specific device, I blame the screen command :)

I think that's a lame excuse to not investigate a potential bug. It
would obviously be helpful if someone who experienced this problem
provided all the details.


//Peter
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Re: usb_debug serial driver protocol

2015-01-28 Thread Peter Stuge
Greg KH wrote:
> > > I've found that screen can leave usb serial ports in an "odd" state,
> > > it's not unique to this specific device, I blame the screen command :)
> > 
> > I think that's a lame excuse to not investigate a potential bug. It
> > would obviously be helpful if someone who experienced this problem
> > provided all the details.
> 
> I think it's bug in screen as minicom and other serial programs seem to
> work just fine.  Next time I run into it, I'll try to write something
> up...

Ah, I meant a potential bug in the kernel.

Userspace should not really be able to cause "odd" things - right? :)


//Peter
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Re: usb_debug serial driver protocol

2015-01-28 Thread Greg KH
On Wed, Jan 28, 2015 at 10:25:16PM +0100, Peter Stuge wrote:
> Greg KH wrote:
> > > Is that some kind of initialization protocol I have to handle? If yes,
> > > where do I find information about it?
> > 
> > The protocol should be part of the USB specification.
> 
> USB debug class devices use no protocol, just transfers of 1-8 bytes,
> used in arbitrary ways by the various device users.
> 
> 
> > I've found that screen can leave usb serial ports in an "odd" state,
> > it's not unique to this specific device, I blame the screen command :)
> 
> I think that's a lame excuse to not investigate a potential bug. It
> would obviously be helpful if someone who experienced this problem
> provided all the details.

I think it's bug in screen as minicom and other serial programs seem to
work just fine.  Next time I run into it, I'll try to write something
up...

thanks,

greg k-h
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Re: usb_debug serial driver protocol

2015-01-28 Thread Greg KH
On Mon, Jan 26, 2015 at 04:37:25PM +0100, Michael Zimmermann wrote:
> Hi,
> 
> I want to use the usb_debug serial driver as a UART shell on my
> (embedded) device, because I just want to use it as a console(without
> a complex protocol so I can easily use putchar and getchar functions).
> 
> This seems to work pretty good except for two things.
> Once upon establishing a connection I receive these data(send in
> 4-word chunks, that's why the address is always the same):
> 0x893d2600: 0041    |A...|
> 0x893d2600: 0054    |T...|
> 0x893d2600: 000d    ||
> 0x893d2600: 0041    |A...|
> 0x893d2600: 0054    |T...|
> 0x893d2600: 000d    ||
> 0x893d2600: 0041    |A...|
> 0x893d2600: 0054    |T...|
> 0x893d2600: 000d    ||
> 0x893d2600: f078007e 007e   |~.x.~...|
> 0x893d2600: f078007e 007e   |~.x.~...|
> 
> Is that some kind of initialization protocol I have to handle? If yes,
> where do I find information about it?

The protocol should be part of the USB specification.

> Another problem is that once the device got closed(by the screen command 
> i.e.).
> I can't communicate with the device anymore.

I've found that screen can leave usb serial ports in an "odd" state,
it's not unique to this specific device, I blame the screen command :)

greg k-h
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usb_debug serial driver protocol

2015-01-26 Thread Michael Zimmermann
Hi,

I want to use the usb_debug serial driver as a UART shell on my
(embedded) device, because I just want to use it as a console(without
a complex protocol so I can easily use putchar and getchar functions).

This seems to work pretty good except for two things.
Once upon establishing a connection I receive these data(send in
4-word chunks, that's why the address is always the same):
0x893d2600: 0041    |A...|
0x893d2600: 0054    |T...|
0x893d2600: 000d    ||
0x893d2600: 0041    |A...|
0x893d2600: 0054    |T...|
0x893d2600: 000d    ||
0x893d2600: 0041    |A...|
0x893d2600: 0054    |T...|
0x893d2600: 000d    ||
0x893d2600: f078007e 007e   |~.x.~...|
0x893d2600: f078007e 007e   |~.x.~...|

Is that some kind of initialization protocol I have to handle? If yes,
where do I find information about it?

Another problem is that once the device got closed(by the screen command i.e.).
I can't communicate with the device anymore.

Thx in regards
Michael
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