Revert "drm/i915: write backlight harder"
This reverts commit cf0a6584. Turns out that cargo-culting breaks systems. Note that we can't revert further, since commit 770c1231 Author: Takashi Iwai <tiwai@suse.de> Date: Sat Aug 11 08:56:42 2012 +0200 drm/i915: Fix blank panel at reopening lid fixed a regression in 3.6-rc kernels for which we've never figured out the exact root cause. But some further inspection of the backlight code reveals that it's seriously lacking locking. And especially the asle backlight update is know to get fired (through some smm magic) when writing specific backlight control registers. So the possibility of suffering from races is rather real. Until those races are fixed I don't think it makes sense to try further hacks. Which sucks a bit, but sometimes that's how it is :( References: http://www.mail-archive.com/intel-gfx@lists.freedesktop.org/msg18788.html Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=47941Tested-by: Takashi Iwai <tiwai@suse.de> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: stable@vger.kernel.org (the reverted commit was cc: stable, too) Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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