Suspend issues with GSM modem?

Lorn Potter lpotter at
Thu Dec 20 01:36:13 CET 2007

Nick Guenther wrote:
> On 12/19/07, Lorn Potter <lpotter at> wrote:
>> Michael Lauer wrote:
>>> "J�rgen P. Tjern�" 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.
> You mean as described
> right?
> Um, an annoying newbie question (but that will probably help a lot of
> people:) could you post the commands for deleting/creating a device? I
> fought with makedevs for an afternoon and couldn't figure it out.
> Thanks,
> -Nick

sudo rm /dev/ttySAC0
sudo mknod /dev/ttySAC0 c 204 64 -m 660
sudo chgrp dialout /dev/ttySAC0

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

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