drm/i915: Use spatio-temporal dithering on PCH

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Spatial dither is better than nothing, but ST is even better.

(from ajax's followup message:)
  I noticed this with:

  http://ajax.fedorapeople.org/YellowFlower.jpg

  set as my desktop background in Gnome on a 1280x800 machine (in
  particular, a Sony Vaio VPCB1 with 6-bit panel and a rather bright black
  level).  Easiest way to test this is by poking at PIPEACONF with
  intel_reg_write directly:

  % sudo intel_reg_write 0x70008 0xc0000040 # no dither
  % sudo intel_reg_write 0x70008 0xc0000050 # spatial
  % sudo intel_reg_write 0x70008 0xc0000054 # ST

  I notice it especially strongly in the relatively flat dark area in the
  top left.  Closer than about 18" I can see a noticeable checkerboard
  pattern with plain spatial dithering.  ST smooths that out; I can still
  tell that it's lacking color precision, but it's not offensive.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

...

This commit is contained in:

Adam Jackson 2010-04-19 15:57:25 -04:00 • committed by Eric Anholt

parent 9e51159c14

commit 0a31a44865

2 changed files with 10 additions and 5 deletions

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5

drivers/gpu/drm/i915/i915_reg.h

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10

drivers/gpu/drm/i915/intel_display.c

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