[Intel-gfx] Screen extremely dim on Dell Latitude D630 after upgrading to Linux kernel-3.14

[Jani Nikula]

On Thu, 22 May 2014, Marc Milgram <mmilgram at redhat.com> wrote:
> After upgrading to linux Kernel-3.14, the screen on my Dell Latitude 
> D630 was nearly unreadably dim.  When I Boot the 3.13 kernel, my screen 
> is bright.

Please file a new bug on DRM/Intel at [1]. Please attach
/sys/kernel/debug/dri/0/i915_opregion and dmesg with drm.debug=0xe
module parameter set.

Also include info whether max_brightness changes for you between 3.13
and 3.14.

Do the later 3.15-rc kernels work for you?


BR,
Jani.


[1] https://bugs.freedesktop.org/enter_bug.cgi?product=DRI




>
> I opened a Bug here: https://bugzilla.redhat.com/show_bug.cgi?id=1094066 
> and others have chimed in that they have the same problem.
>
> I bisected the kernel, and found the following commit is responsible for 
> this problem:
>
> b35684b8fa94e04f55fd38bf672b737741d2f9e2 is the first bad commit
> commit b35684b8fa94e04f55fd38bf672b737741d2f9e2
> Author: Jani Nikula <jani.nikula at intel.com  <mailto:jani.nikula at intel.com>>
> Date:   Thu Nov 14 12:13:41 2013 +0200
>
>      drm/i915: do full backlight setup at enable time
>      
>      We should now have all the information we need to do a full
>      initialization of the backlight registers.
>      
>      v2: Keep QUIRK_NO_PCH_PWM_ENABLE for now (Imre).
>      
>      Signed-off-by: Jani Nikula <jani.nikula at intel.com  <mailto:jani.nikula at intel.com>>
>      Reviewed-by: Imre Deak <imre.deak at intel.com  <mailto:imre.deak at intel.com>>
>      Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch  <mailto:daniel.vetter at ffwll.ch>>
>
> :040000 040000 0aae5515ca62ff1bfd2e1c2769e30c58b016ffeb 01c2f8cd145f8cf29730908d52e7e89b787a059e M	drivers
>
> I can find my way around the kernel, but haven't hit this area before.
>
> Any help is appreciated.
>
> Marc Milgram
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Jani Nikula, Intel Open Source Technology Center