[Intel-gfx] Trouble with dell latitude E6420

[Daniel Vetter]

On Tue, Jun 26, 2012 at 03:08:32PM -0400, Giacomo Comes wrote:
> I have a dell latitude E6420 with Sandybridge Mobile (GT2).
> Since I got it (about one year ago), it has been a nightmare to run linux on it.
> At the beginning I installed openSUSE 11.4 (kernel 2.6.37.6) and the laptop
> would freeze almost immediately. After that I waited for newer kernels in order to
> see if things would improve. They did improve indeed and finally with kernel 3.0
> I was able to run linux (openSUSE 11.4) without laptop freeze or screen issue.
> Unfortunately, the only kernel that works with my laptop is 3.0. Newer kernel
> (3.1, 3.2, 3.3 and 3.4) do not work.
> This is what happen if I run kernel 2.6.39, 3.1, 3.2, 3.3 and 3.4:
> The laptop boot and does the boot process fine. At the end of the boot process X
> starts and here the problem appears (about 50% of the times):
> the screen goes black on the left side (about 2/3 of the whole screen) with white
> stripes to the right side (the remaining 1/3).
> The laptop is not dead: I can remotely login or I can perform a clean shutdown
> if I press the power button, but the screen is totally dead.
> Another strange issue is that after a bad boot (with the black screen) at the
> next reboot the screen will start to flicker. The flickering will last some time
> and it will become less intense as the time goes until it will disappear completely.
> The funny thing is that the intensity of flicker depends on how long I keep the
> black screen. If, after the boot process, the black screen appears and I reboot
> the laptop immediately, then the flicked is moderate and it disappear after
> 1 or 2 minutes. If I keep the black screen for 1 minute or more, then after the
> reboot the flicker is very intense and it takes much more to fade.
> 
> Right now I run openSUSE 12.1 on the laptop, but I had to perform the following
> trick: because openSUSE 12.1 ships with kernel 3.1, in order to make openSUSE run on my
> laptop I have the options:
> 1) downgrade to kernel 3.0 (I use 3.0.7)
> 2) recompile the openSUSE kernel 3.1 replacing the directory drivers/gpu/drm/i915
> with the content of the same directory from kernel 3.0 source tree.
> 
> I choose the second option as I can run the latest openSUSE kernel with patches
> and fixes.
> 
> I have searched google to see if other users have my same problem and
> I have found few references to a problem similar to mine:
> 
> http://lists.freedesktop.org/archives/intel-gfx/2011-March/009822.html
> http://www.gossamer-threads.com/lists/linux/kernel/1474140
> https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/794474
> 
> But in none there is a mention on how to fix the problem.
> 
> Is there any chance to improve the intel kernel driver to make it work
> for my laptop as it was in kernel 3.0?

Sure, we're always working to fix odd bugs ;-)

> I can provide any information/testing as needed.

A few things for you to do, pretty much random order:
- Can you try out the latest drm-intel-next-queued branch from the
  drm-intel git repo at:

http://cgit.freedesktop.org/~danvet/drm-intel

  This is the basic step to ensure that we haven't fixed your bug already
  in the latest code.
- Please attach xrandr --verbos and full dmesg when booting with
  drm.debug=0xe (take a working kernel, doesn't matter that much).
- If you can, please bisect which commit exactly introduced the regression
  betwen 3.0 and 3.1. That usually helps a _lot_ in tracking down these
  bugs.

Yours, Daniel
-- 
Daniel Vetter
Mail: daniel at ffwll.ch
Mobile: +41 (0)79 365 57 48