drm/i915: Clear any existing dither mode prior to enabling spatial dithering
We cannot the initial configuration set by the BIOS not to have a dither
mode enabled which conflicts with our enabling the Spatial Temporal 1
dither mode for PCH. In particular, the BIOS may either enable temporal
dithering or the Spatial Temporal 2 with the result that we enable pure
temporal dithering. Temporal dithering looks bad and is perceived as a
flicker.
Fixes:
Bug 29248 - [Arrandale] Annoying flicker on internal panel, goes away
after suspend to RAM
https://bugs.freedesktop.org/show_bug.cgi?id=29248
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>
1 file changed