On Sun, Mar 01, 2015 at 12:30:01PM +0300, Andrey Skvortsov wrote: > On 01 Mar, Chris Wilson wrote: > > On Sun, Mar 01, 2015 at 12:57:01AM +0300, Andrey Skvortsov wrote: > > > On 28 Feb, Chris Wilson wrote: > > > > On Sat, Feb 28, 2015 at 03:20:37PM +0300, Andrey Skvortsov wrote: > > > > > Unfortunately this is not the last bug, that breaks i915/drm working > > > > > on my laptop. Sometimes system successfully loads with couple > > > > > warnings mentioned in > > > > > previous mail: > > > > > > > > > > [ 26.922953] WARNING: CPU: 1 PID: 767 at > > > > > drivers/gpu/drm/i915/i915_gem.c:4525 i915_gem_free_object+0x13f/0x288 > > > > > [i915]() > > > > > [ 26.922954] WARN_ON(obj->frontbuffer_bits) > > > > > > > > That's inocuous, but for the serious hang, you may want to try > > > > video=SVIDEO-1:d on the kernel commandline to workaround the hang. > > > > (Check > > > > /sys/class/drm/card/ for the actual name of the connector for TV). I > > > > think Ville mentioned he was looking/looked at the atomic-vs-load_detect > > > > changes that is at the heart of the issue here. (Admittedly he did say > > > > it was worthy of a drink or two.) > > > > -Chris > > > > > > Thank you for the help. I've tried to add to the kernel command line > > > 'video=card0-SVIDEO-1:d video=card0-VGA-1:d'. But despite of that > > > kernel crashes with 'BUG: unable to handle kernel NULL pointer > > > dereference at' occasionally. > > > > Remove the card0- and combine both into a single video= stanza: > > video=SVIDEO-1:d,VGA-1:d > > I've just tried that, but the crash with NULL pointer dereference still > happens.
Drat. In hindsight it should have been obvious since the crash is from the driver probing the hardware during init and not the runtime output detection. :| -Chris -- Chris Wilson, Intel Open Source Technology Centre
