From: Adam Jackson <ajax@redhat.com>
Date: Mon, 19 Apr 2010 19:57:25 +0000 (-0400)
Subject: drm/i915: Use spatio-temporal dithering on PCH
X-Git-Tag: v2.6.35-rc1~451^2~12^2~9
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0a31a448659d48cbc38f5e7520d8a65f8f1f8276;p=pandora-kernel.git

drm/i915: Use spatio-temporal dithering on PCH

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>
---

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