linux/drivers/gpu
Chris Wilson 7782de3bd6 drm/i915: Disable FBC across page-flipping
Page-flipping updates the scanout address, nukes the FBC compressed
image and so forces an FBC update so that the displayed image remains
consistent. However, page-flipping does not update the FBC registers
themselves, which remain pointing to both the old address and the old
CPU fence. Future updates to the new front-buffer (scanout) are then
undetected!

This first approach to demonstrate the issue and highlight the fix,
simply disables FBC upon page-flip (a recompression will be forced on
every flip so FBC becomes immaterial) and then re-enables FBC in the
page-flip finish work function, so that the FBC registers are now
pointing to the new framebuffer and front-buffer rendering works once
more.

Ideally, we want to only re-enable FBC after page-flipping is complete,
as otherwise we are just wasting cycles and power (with needless
recompression) whilst the page-flipping application is still running.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=33487
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Keith Packard <keithp@keithp.com>
2011-07-08 10:23:15 -07:00
..
drm drm/i915: Disable FBC across page-flipping 2011-07-08 10:23:15 -07:00
stub i915: select VIDEO_OUTPUT_CONTROL for ACPI_VIDEO 2011-04-13 09:10:25 +10:00
vga Merge branch 'drm-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6 2011-05-24 12:06:40 -07:00
Makefile