drm/i915: Fix sync to vblank when VGA output is turned off
authorLi Peng <peng.li@linux.intel.com>
Mon, 9 Nov 2009 04:51:22 +0000 (12:51 +0800)
committerEric Anholt <eric@anholt.net>
Tue, 1 Dec 2009 18:27:40 +0000 (10:27 -0800)
commit778c902640530371a169ad1c03566e7c51b09874
tree4230fb7e4f79e00931c1efcf2b88cfec285ae7ff
parent27dfaf4f5825a119305db1bc63bef30ed400e376
drm/i915: Fix sync to vblank when VGA output is turned off

In current vblank-wait implementation, if we turn off VGA output,
drm_wait_vblank will still wait on the disabled pipe until timeout,
because vblank on the pipe is assumed be enabled. This would cause
slow system response on some system such as moblin.

This patch resolve the issue by adding a drm helper function
drm_vblank_off which explicitly clear vblank_enabled[crtc], wake up
any waiting queue and save last vblank counter before turning off
crtc. It also slightly change drm_vblank_get to ensure that we will
will return immediately if trying to wait on a disabled pipe.

Signed-off-by: Li Peng <peng.li@intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
[anholt: hand-applied for conflicts with overlay changes]
Signed-off-by: Eric Anholt <eric@anholt.net>
drivers/gpu/drm/drm_irq.c
drivers/gpu/drm/i915/intel_display.c
include/drm/drmP.h