Re: no video output after suspend after "drm/i915: force mode set at lid open time"

[Jesse Barnes <jbarnes@virtuousgeek.org>]

On Sun, 25 Oct 2009 21:57:32 +0100
Riccardo Magliocchetti <riccardo.magliocchetti@gmail.com> wrote:

> Hello,
> 
> i lost video output, screen stays black, after suspend after commit 
> c1c7af60892070e4b82ad63bbfb95ae745056de0 "drm/i915: force mode set at 
> lid open time".
> 
> I'm attaching my dmesg with 2.6.32-rc5 (actually
> 964fe080d94db82a3268443e9b9ece4c60246414), my bisect log and my
> config.
> 
> git bisect response:
> 
> c1c7af60892070e4b82ad63bbfb95ae745056de0 is the first bad commit
> commit c1c7af60892070e4b82ad63bbfb95ae745056de0
> Author: Jesse Barnes <jbarnes@virtuousgeek.org>
> Date:   Thu Sep 10 15:28:03 2009 -0700
> 
>      drm/i915: force mode set at lid open time
> 
>      Some laptop platforms will disable pipes and/or planes at lid
> close time
>      and not restore them when the lid is opened again.  So catch the
> lid event, and if the lid was opened, force a mode restore.
> 
>      Fixes fdo bug #21230.
> 
>      Acked-by: Matthew Garrett <mjg@redhat.com>
>      Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
>      Signed-off-by: Eric Anholt <eric@anholt.net>

I wonder if this is the real problem...  This patch introduced an issue
that was fixed by 06891e27a9b5dba5268bb80e41a283f51335afe7 that could
cause a blank screen on lid open or resume, depending on how lid events
were delivered.  Should be easy enough to test though, you can remove
the whole

+       if (acpi_lid_open())
+               drm_helper_resume_force_mode(dev);

block and see if that also helps (in the current tree there's a lock
taken around the force_mode call, you'll need to remove those lines too
for testing).
-- 
Jesse Barnes, Intel Open Source Technology Center