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>
Tue, 20 Sep 2011 01:02:51 +0000 (18:02 -0700)
commit7cd015a0a37265e23bbdce7ce8f7e00507abe9ed
tree0abfb84a29cdc757d90a38abe3f07324e40421ff
parentb6fd41e29dea9c6753b1843a77e50433e6123bcb
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