Suspend issues with GSM modem?

Lorn Potter lpotter at
Wed Dec 19 22:43:38 CET 2007

Michael Lauer wrote:
> "Jørgen P. Tjernø" wrote:
>> Hash: SHA1
>> I've recently left my Neo1973 silent and lonely, due to being swamped
>> with projects and school. But smoe time ago I heard there was an issue
>> with the GSM modem after resuming from suspend - and this prevents the
>> batterytime to getting even close to bearable.
> Right.
>> Is this still present?
> Unfortunately yes.
>> What're the specifics of the issue, and are the
>> OpenMoko-guys working on it? Is it a software issue, or an actual
>> hardware defect?
> IIRC this is missing some glue in the kernel to set the serial port
> and/or modem back to a known state before gsmd continues to read from
> it. If you can't find a bug in bugzilla about that, please open one.
> Feel free to rate it as BLOCKER.

I am not so sure that's necessarily the whole issue. Of course, I could
be wrong.

I haven't tried this with openmoko/gsmd, but if you delete the ttySAC0
and then create it again before you power it up (like I do with the
qtopia startup script), at least with Qtopia, suspend/resume starts
working more or less correctly. (this doesn't matter if there is a
/dev/ttySAC0 entry in bootloader or not) It even wakes up for an
incoming voice call. More or less. If it were a simply a matter of
putting the chip/serial device into a known state on resume before you
read from it, this would probably not work at all with Qtopia.

Unfortunately, the device (at least mine), occasionally gets into a
state where it won't wake up, (or powers itself down), and requires a
battery pull. But I have gone at least a day and half without plugging
in the neo (could be two), and having a workable phone.

Lorn 'ljp' Potter
Software Engineer, Systems Group, MES, Trolltech

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