drm/i915: do not disable backlight on vgaswitcheroo switch off
authorJani Nikula <jani.nikula@intel.com>
Thu, 25 Jul 2013 11:31:30 +0000 (14:31 +0300)
committerDaniel Vetter <daniel.vetter@ffwll.ch>
Wed, 7 Aug 2013 09:57:09 +0000 (11:57 +0200)
commit3f577573cd5482a32f85bd131e52f7cb4b9ac518
tree87c7eee0318624bbf90bf318646d0d5471bb41b2
parent3eaba51cd399f5362a9fd9ebd5fb8b625b454271
drm/i915: do not disable backlight on vgaswitcheroo switch off

On muxed systems, the other vgaswitcheroo client may depend on i915 to
handle the backlight. We began switching off the backlight since

commit a261b246ebd552fd5d5a8ed84cc931bb821c427f
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu Jul 26 19:21:47 2012 +0200

    drm/i915: disable all crtcs at suspend time

breaking backlight on discreet graphics in (some) muxed systems.

Keep the backlight on when the state is changed through vgaswitcheroo.

Note: The alternative would be to add a quirk table to achieve the same
based on system identifiers, but AFAICS it would asymptotically approach
effectively the same as this patch as more IDs are added, but with the
maintenance burden of the quirk table.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=55311
Tested-by: Fede <fedevx@yahoo.com>
Tested-by: Aximab <laurent.debian@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=59785
Tested-by: sfievet <sebastien.fievet@free.fr>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drivers/gpu/drm/i915/intel_panel.c