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

Dr. H. Nikolaus Schaller hns at goldelico.com
Fri Feb 10 16:07:03 CET 2012

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?

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:


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.


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