From c2a618dd05fc462dc828014b223de4afa50355b2 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Mon, 23 Jun 2014 21:19:41 +0300 Subject: [PATCH] drm/i915: Wait for vblank after enabling the primary plane on BDW MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit BDW signals the flip done interrupt immediately after the DSPSURF write when the plane is disabled. This is true even if we've already armed DSPCNTR to enable the plane at the next vblank. This causes major problems for our page flip code which relies on the flip done interrupts happening at vblank time. So what happens is that we enable the plane, and immediately allow userspace to submit a page flip. If the plane is still in the process of being enabled when the page flip is issued, the flip done gets signalled immediately. Our DSPSURFLIVE check catches this to prevent premature flip completion, but it also means that we don't get a flip done interrupt when the plane actually gets enabled, and so the page flip is never completed. Work around this by re-introducing blocking vblank waits whenever we enable the primary plane. To avoid these blocking vblank waits we should start using the vblank interrupt instead of the flip done interrupt to complete page flips. But that's material for another pathc. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=79354 Cc: stable@vger.kernel.org Signed-off-by: Ville Syrjälä --- drivers/gpu/drm/i915/intel_display.c | 9 +++++++++ drivers/gpu/drm/i915/intel_sprite.c | 8 ++++++++ 2 files changed, 17 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index fa77557..5d4795f 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -2134,6 +2134,7 @@ void intel_flush_primary_plane(struct drm_i915_private *dev_priv, static void intel_enable_primary_hw_plane(struct drm_i915_private *dev_priv, enum plane plane, enum pipe pipe) { + struct drm_device *dev = dev_priv->dev; struct intel_crtc *intel_crtc = to_intel_crtc(dev_priv->pipe_to_crtc_mapping[pipe]); int reg; @@ -2153,6 +2154,14 @@ static void intel_enable_primary_hw_plane(struct drm_i915_private *dev_priv, I915_WRITE(reg, val | DISPLAY_PLANE_ENABLE); intel_flush_primary_plane(dev_priv, plane); + + /* + * BDW signals flip done immediately if the plane + * is disabled, even if the plane enable is already + * armed to occur at the next vblank :( + */ + if (IS_BROADWELL(dev)) + intel_wait_for_vblank(dev, intel_crtc->pipe); } /** diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c index 0e3fd5c..985317e 100644 --- a/drivers/gpu/drm/i915/intel_sprite.c +++ b/drivers/gpu/drm/i915/intel_sprite.c @@ -691,6 +691,14 @@ intel_post_enable_primary(struct drm_crtc *crtc) struct intel_crtc *intel_crtc = to_intel_crtc(crtc); /* + * BDW signals flip done immediately if the plane + * is disabled, even if the plane enable is already + * armed to occur at the next vblank :( + */ + if (IS_BROADWELL(dev)) + intel_wait_for_vblank(dev, intel_crtc->pipe); + + /* * FIXME IPS should be fine as long as one plane is * enabled, but in practice it seems to have problems * when going from primary only to sprite only and vice -- 1.8.5.5