drm/i915: framebuffer compression for pre-GM45
This patch adds framebuffer compression (good for about ~0.5W power
savings in the best case) support for pre-GM45 chips. GM45+ have a new,
more flexible FBC scheme that will be added in a separate patch.
FBC can't always be enabled: the compressed buffer must be physically
contiguous and reside in stolen space. So if you have a large display
and a small amount of stolen memory, you may not be able to take
advantage of FBC. In some cases, a BIOS setting controls how much
stolen space is available. Increasing this to 8 or 16M can help.
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
5 files changed