Re: Resume from S2R fails after dpm_resume()

Nigel Cunningham
2007-03-02T21:32:20Z

Hi.

On Fri, 2007-03-02 at 07:25 -0700, Tim Gardner wrote:
> Pavel Machek wrote:
> > Hi!
> >
> >> I instrumented 2.6.21-rc1 base/power/resume.c device_resume() with
> >> TRACE_RESUME(0) as the last statement in the function. Sure enough it
> >> was the last hash value in the RTC after a hard reboot when resume failed:
> >>
> >> [ 12.028820] hash matches drivers/base/power/resume.c:104
> >>
> >> The machine appears to be absolutely wedged after initiating resume by
> >> pressing the power button. The disk flashes for a half second or so,
> >> then thats it.
> >>
> >> It is a Dell XPS, BIOS rev A04. I'm using 'echo 1 > /sys/power/pm_trace;
> >> echo mem > /sys/power/state' to initiate the S2R sequence.
> >>
> >> Any suggestions on where to go from here?
> >
> > Did it work ok in 2.6.20? Can you try to get video working/get serial
> > console/something?
> > Pavel
>
> Pavel,
>
> The last version that worked well was Ubuntu Edgy (2.6.17). It was
> broken by 2.6.18. I have not started the 'git bisect' process, instead
> I've been trying to figure out why it doesn't work in 2.6.21-rc2. Using
> the TRACE_RESUME macro I've drilled down to
> kernel/printk.c:__call_console_drivers. So far the last trace info that
> I have is just before the call to con->write(). I'm trying to figure out
> what driver has registered as the console (intel_agp or agpgart?).
>
> Am I banging my head on a known problem?

Tim, it's possible that the problem you're seeing is completely
different to the one Pavel is looking for. Given that you're down to
looking in console write code, I wonder if it's related to the changes
to console suspending that were done around that time. I'd suggest
either looking in LKML or Linux-PM archives for a commit related to
suspending the console, or doing your git bisect.

Regards,

Nigel