On gen2-4, we have a separate pageflip prepare/finish phase. The intent of the stall check is to detect when we have incurred a delay, potentially indefinite, after the pageflip is submitted and before the flip is processed by the hardware. However, our notion of INTEL_FLIP_PENDING/INTEL_FLIP_COMPLETE do not tally with how we set the values during prepare/finish and the current stall check erroneously assumes that when the pending value >= COMPLETE, the driver has seen the hardware completion flag. But what the driver actually means, is that it has seen the acknowlegement that the flip is queued and is now pending the completion event. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=85888 Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> --- drivers/gpu/drm/i915/intel_display.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 70a75136bc61..0c43d970dbf9 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -9707,8 +9707,8 @@ static bool __intel_pageflip_stall_check(struct drm_device *dev, struct intel_unpin_work *work = intel_crtc->unpin_work; u32 addr; - if (atomic_read(&work->pending) >= INTEL_FLIP_COMPLETE) - return true; + if (atomic_read(&work->pending) < INTEL_FLIP_COMPLETE) + return false; if (!work->enable_stall_check) return false; -- 2.1.3 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
