[Intel-gfx] [C220] Display goes blank with PCH PWM1 enabled warning in intel_display.c:7376/6900

[Catalin Hritcu]

On Mon, Nov 10, 2014 at 11:47 AM, Jani Nikula
<jani.nikula at linux.intel.com> wrote:
> On Mon, 10 Nov 2014, Catalin Hritcu <catalin.hritcu at gmail.com> wrote:
>> Dear Intel graphics driver community,
>>
>> I'm a user experiencing display problems and joined this mailing list
>> to get some help with filing a proper bug report. In particular,
>> I'm unsure against which component I should file the following problem.
>
> Please file a new bug against DRM/Intel at [1].
>
> Reference your mail on the mailing list.
>
> Smells like pm refcounting problems.

I've filed a new bug as instructed:
https://bugs.freedesktop.org/show_bug.cgi?id=86105

> Attach dmesg with
> drm.debug=14 module parameter set, from boot to the problem.

I'll try to produce a dmesg log with drm.debug=14 set from the boot.
This will take a while since restarting causes the problem to go away
and it takes days or even weeks for the problem to reappear. The
problem is happening right now though, so if someone can suggest a way
to pass drm.debug=14 without rebooting the machine this I could
provide some preliminary information right away. I've tried this:

[hritcu at detained i915]$ sudo sysctl drm.debug=14
[sudo] password for hritcu:
sysctl: cannot stat /proc/sys/drm/debug: No such file or directory
[hritcu at detained i915]$ ls /proc/sys
abi  debug  dev  fs  kernel  net  vm

but I have no drm directory in /proc/sys.

Many thanks,
Catalin