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| author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2012-10-04 19:20:03 +0200 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2012-10-08 19:31:04 +0200 |
| commit | 6ce9410047f9f06c1b3336d5215402b77d6fd70f (patch) | |
| tree | 59b134cd2408654a10993452faa090ea5e85f6f0 /drivers/gpu | |
| parent | c77d7162a7ae451c2e895d7ef7fbeb0906107472 (diff) | |
| download | linux-6ce9410047f9f06c1b3336d5215402b77d6fd70f.tar.bz2 | |
drm/i915: paper over a pipe-enable vs pageflip race
I've discovered this on my ivb machine while stress-testing the new
flip_tests. Only harmful effect observed is that the timestamp is a
bit bogus.
Note that this is empirical duct-tape: I've noticed that we seem to
only ever miss the very first vblank irq right after enabling the
pipe. And with this hack applied I couldn't reproduce the failure case
anywhere else any more.
Tested-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'drivers/gpu')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_display.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 67912febb322..9cecfd73b0b1 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -3253,6 +3253,16 @@ static void ironlake_crtc_enable(struct drm_crtc *crtc) if (HAS_PCH_CPT(dev)) intel_cpt_verify_modeset(dev, intel_crtc->pipe); + + /* + * There seems to be a race in PCH platform hw (at least on some + * outputs) where an enabled pipe still completes any pageflip right + * away (as if the pipe is off) instead of waiting for vblank. As soon + * as the first vblank happend, everything works as expected. Hence just + * wait for one vblank before returning to avoid strange things + * happening. + */ + intel_wait_for_vblank(dev, intel_crtc->pipe); } static void ironlake_crtc_disable(struct drm_crtc *crtc) |