[SOLVED] kernel 3.2.0 - blank screen on resume

kolcon · Last edited by kolcon on Fri Jan 27, 2012 8:29 pm; edited 1 time in total

Hello,

after moving from gentoo-sources-3.1.5 to 3.2.0-r1 (copied over .config) I cannot wake from suspend anymore.

Or, should I say, the computer wakes fine, only I cannot see anything on the (blank) screen.
But the notebook works, I can even ssh to it.

I found out in the log file line related to this:
kernel: [drm:intel_dp_complete_link_train] *ERROR* failed to train DP, aborting

I cannot get the screen back, even when trying things like xset force dpms off (or on) or playing with
xrandr.

What would you recommmend me to try or do?

Thanks

Lubos

Hu · Administrator Joined: 06 Mar 2007 Posts: 23193

If a bug report has not yet been filed, then please file one. If you find one which has been filed, please post the link(s) here for the benefit of others who encounter the problem.

If you have time, expertise, and motivation, you could try performing a git bisect to search for the specific commit which caused this. We know that v3.1.5 works for you and v3.2 fails, so there are only 12695 commits to test, which should take about 14 iterations. If you get lucky and the break is in the drivers/gpu/drm/i915 directory, then there are only 126 commits to test, which should take about 7 iterations. In both cases, the iteration count could be higher if you get unlucky and hit a broken commit or the bisect is not able to pick an optimal midpoint.

kolcon · Posted: Sun Jan 08, 2012 2:13 pm Post subject:

Thanks, I have done what you suggest.
The bug is here : https://bugs.gentoo.org/show_bug.cgi?id=398149

The culprit commit is :
cd9dde44f47501394b9f0715b6a36a92aa74c0d0 is the first bad commit
commit cd9dde44f47501394b9f0715b6a36a92aa74c0d0
Author: Adam Jackson <ajax@redhat.com>
Date: Fri Oct 14 12:43:49 2011 -0400

drm/i915/dp: Fix the math in intel_dp_link_required

The previous code was confused about units, which is pretty reasonable
given that the units themselves are confusing.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Keith Packard <keithp@keithp.com>

:040000 040000 3c0a0f38fc6482a401340e03fa3fbd687d11eda4 294673b782b3ecc93540f46f7721d385bd30cfac M drivers

kolcon · Posted: Sat Jan 21, 2012 10:04 am Post subject:

... still does not work with 3.3-rc1...

toralf · Posted: Sat Jan 21, 2012 10:19 am Post subject:

YOu should post the bisect results to the linux kernel mailing list directly : linux-kernel@vger.kernel.org

kolcon · Posted: Sat Jan 21, 2012 10:32 am Post subject:

kolcon · Posted: Fri Jan 27, 2012 8:30 pm Post subject:

toralf · Posted: Sat Jan 28, 2012 9:07 am Post subject:

Yep - in general it is a good idea to post such bugs directly to the LKML or to the appropriate Bugzilla sites ate freedesktop.org.

Joseph K. · Posted: Mon Feb 06, 2012 12:52 pm Post subject:

Hmmm, I didn't hit this bug on my i915 laptop, but I did just hit it on my new i965 laptop. Any chance that the Gentoo devs will backport a patch to 3.2.x?

Hu · Administrator Joined: 06 Mar 2007 Posts: 23193