[Intel-gfx] [REGRESSION] system hang on ILK/SNB/IVB

[Tomi Sarvela]

Hi Lukas,

Ran this patch through the farm, and it seems that this patch might've helped 
HSW, maybe even BSW.

ILK, IVB and SNB are still hanging hard to the same igt-test,
kms_pipe_crc_basic at suspend-read-crc-pipe-?

I'll try to make a kernel with the changes you proposed, but as I'm not 
familiar with the driver innards, it might take a while.

Tomi


On Thursday 31 March 2016 22:35:17 Lukas Wunner wrote:
> Hi Tomi,
> 
> On Thu, Mar 31, 2016 at 10:21:16AM +0300, Tomi Sarvela wrote:
> > The problem with the results in your link is that there is no HSW, ILK,
> > IVB
> > or SNB results. This might give the impression that everything is well.
> > 
> > Most damning is lack of HSW-gt2 and SNB-dellxps: those machines hang on to
> > APC, and have run quite stably for every Patchwork run. The case isn't
> > strong enough yet that series should fail if either of those won't run,
> > but it might be so in future.
> 
> So my patch seeking to fix the hangs has passed Romania CI with "success":
> https://patchwork.freedesktop.org/series/5125/
> 
> However I don't see HSW-gt2 and SNB-dellxps in their hardware lineup.
> And I would still like to know what the actual cause of the hangs is
> since they do not occur on my IVB laptop.
> 
> If you get the chance maybe you can repeat the test and include a
> "dump_stack();" at the beginning of intel_fbdev_output_poll_changed()
> and intel_fbdev_restore_mode(). This should show in the logs which of
> the two functions is called during suspend/resume and from where it's
> called. My guess is that this particular hardware causes a hotplug
> signal to be generated upon waking up. If the hangs do not stop with
> this patch, booting with "no_console_suspend" should at least show
> what's going on.
> 
> Thank you & best regards,
> 
> Lukas