[Gta04-owner] /dev/ttyHS3 renames after resume to /dev/ttyHS6

Dr. H. Nikolaus Schaller hns at goldelico.com
Fri Feb 10 17:08:28 CET 2012


Am 10.02.2012 um 16:27 schrieb Flemming Richter Mikkelsen:

> On Fri, Feb 10, 2012 at 16:07, Dr. H. Nikolaus Schaller <hns at goldelico.com> wrote:
> 
> Am 10.02.2012 um 15:46 schrieb Radek Polak:
> 
> > Hi,
> > i found a problem with modem serial device. Probably after suspend/resume the
> > device node is renamed from /dev/ttyHS3->/dev/ttyHS6 and i cant send AT
> > commands then. Attached is dmesg output, you can search for ttyHS6 to find the
> > place.
> >
> > These are all /dev/ttyHS before suspend:
> >
> >       ttyHS0  ttyHS1  ttyHS2  ttyHS3  ttyHS4  ttyHS5
> >
> > and this is how it looked after resume:
> >
> >       ttyHS0  ttyHS1  ttyHS2  ttyHS4  ttyHS5  ttyHS6
> 
> Hm. Maybe the driver knows that ttyHS3 is active before
> resume and therefore shuts it down differently from the other ports?
>  
> grep ttyH dmesg.txt tells us that for ttyHS{0,1,2,4,5} the devices is shut down:
>    device_unregister
>    device_create_release
> but nothing similar for ttyHS3.

This appears to be a good hint.

>  Maybe this is because we don't power off the modem completely?

Well, then it should handle all /dev/ttyHS ports in the same way.
They are all to communicate with the modem.

Or because it is in use (opened)?

Ah, please try:

sleep 1000 </dev/ttyHS0    # this is the diagnostics ports

then suspend and see if ttyHS0 also remains registered.


>  
> But the driver code is open and I think it is in drivers/net/usb/hso.c
> 
> So it should be possible (at least in theory) to understand how this
> renumbering happens.
> 
> >
> > This is with kernel 3.2 and i have udev running on my system (could it be the
> > problem?)
> >
> > Another question: i am always assuming /dev/ttyHS3 as modem device for AT
> > commands. Is it correct?
> 
> Not 100%, although it is after a Reset.
> 
> Please look into the 'root/dial' or 'root/pin' script:
> 
>        http://download.goldelico.com/gta04/unstable/config.tgz
> 
> It scans the /sys entries to locate the "Application" port, even if
> it is being renumbered. During our automatic hardware tests we do
> a AT_ORESET and I have observed that sometimes ttyHS3 and ttyHS4
> have swapped their roles.
> 
> Scanning /sys is also recommended by OPTION.
> 
> Nikolaus
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> 
> 
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