drm/i915: Enable dither whenever display bpc < frame buffer bpc
authorKeith Packard <keithp@keithp.com>
Mon, 5 Sep 2011 18:53:21 +0000 (11:53 -0700)
committerKeith Packard <keithp@keithp.com>
Wed, 21 Sep 2011 21:52:40 +0000 (14:52 -0700)
commit578393cd1e6ebe2979664f11df630126c3f348a8
treeb4400b419662d459606616a0bf618320c1b47802
parent88ef4e3f4f616462b78a7838eb3ffc3818d30f67
drm/i915: Enable dither whenever display bpc < frame buffer bpc

We want to enable dithering on any pipe where the frame buffer has
more color resolution than the output device.

The previous code was incorrectly clamping the frame buffer bpc to the
display bpc, effectively disabling dithering all of the time as the
computed frame buffer bpc would never be larger than the display bpc.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reported-by: Oliver Hartkopp <socketcan@hartkopp.net>
Tested-by: Oliver Hartkopp <socketcan@hartkopp.net>
drivers/gpu/drm/i915/intel_display.c