From: Paulo Zanoni Date: Thu, 19 Dec 2013 21:12:31 +0000 (-0200) Subject: drm/i915: remove the vblank_wait hack from HSW+ X-Git-Tag: next-20140306~57^2~1^2~39 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=3fddd40739de9c08099d1d488d24c42e0c210d6b;p=karo-tx-linux.git drm/i915: remove the vblank_wait hack from HSW+ When I forked haswell_crtc_enable I copied all the code from ironlake_crtc_enable. The last piece of the function contains a big comment with a call to intel_wait_for_vblank. After this fork, we rearranged the Haswell code so that it enables the planes as the very last step of the modeset sequence, so we're sure that we call intel_enable_primary_plane after the pipe is really running, so the vblank waiting functions work as expected. I really believe this is what fixes the problem described by the big comment, so let's give it a try and get rid of that intel_wait_for_vblank, saving around 16ms per modeset (and init/resume). We can always revert if needed :) Signed-off-by: Paulo Zanoni Reviewed-by: Jesse Barnes Signed-off-by: Daniel Vetter --- diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 0523419bc485..8215ba23cb0b 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -3761,16 +3761,6 @@ static void haswell_crtc_enable(struct drm_crtc *crtc) * to change the workaround. */ haswell_mode_set_planes_workaround(intel_crtc); haswell_crtc_enable_planes(crtc); - - /* - * 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_pfit_disable(struct intel_crtc *crtc)