[Intel-gfx] [PATCH 2/2] drm/i915: Wait for pending flips in intel_pipe_set_base()

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

intel_pipe_set_base() never actually waited for any pending page flips
on the CRTC. It looks like it tried to, by calling intel_finish_fb() on
the current front buffer. But the pending flips were actually tracked
in the BO of the previous front buffer, so the call to intel_finish_fb()
never did anything useful.

Now even the pending_flip counter is gone, so we should just
use intel_crtc_wait_for_pending_flips(), but since we're already holding
struct_mutex when we would call that function, we need another version
of it, that itself doesn't lock struct_mutex.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_display.c |   54 ++++++++++++++++++++--------------
 1 files changed, 32 insertions(+), 22 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 83e16f8..8f56d9a 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2176,9 +2176,6 @@ intel_finish_fb(struct drm_framebuffer *old_fb)
 	bool was_interruptible = dev_priv->mm.interruptible;
 	int ret;
 
-	wait_event(dev_priv->pending_flip_queue,
-		   atomic_read(&dev_priv->mm.wedged));
-
 	/* Big Hammer, we also need to ensure that any pending
 	 * MI_WAIT_FOR_EVENT inside a user batch buffer on the
 	 * current scanout is retired before unpinning the old
@@ -2221,6 +2218,37 @@ static void intel_crtc_update_sarea_pos(struct drm_crtc *crtc, int x, int y)
 	}
 }
 
+static bool intel_crtc_has_pending_flip(struct drm_crtc *crtc)
+{
+	struct drm_device *dev = crtc->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	unsigned long flags;
+	bool pending;
+
+	if (atomic_read(&dev_priv->mm.wedged))
+		return false;
+
+	spin_lock_irqsave(&dev->event_lock, flags);
+	pending = to_intel_crtc(crtc)->unpin_work != NULL;
+	spin_unlock_irqrestore(&dev->event_lock, flags);
+
+	return pending;
+}
+
+static void intel_crtc_wait_for_pending_flips_locked(struct drm_crtc *crtc)
+{
+	struct drm_device *dev = crtc->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	if (crtc->fb == NULL)
+		return;
+
+	wait_event(dev_priv->pending_flip_queue,
+		   !intel_crtc_has_pending_flip(crtc));
+
+	intel_finish_fb(crtc->fb);
+}
+
 static int
 intel_pipe_set_base(struct drm_crtc *crtc, int x, int y,
 		    struct drm_framebuffer *fb)
@@ -2254,8 +2282,7 @@ intel_pipe_set_base(struct drm_crtc *crtc, int x, int y,
 		return ret;
 	}
 
-	if (crtc->fb)
-		intel_finish_fb(crtc->fb);
+	intel_crtc_wait_for_pending_flips_locked(crtc);
 
 	ret = dev_priv->display.update_plane(crtc, fb, x, y);
 	if (ret) {
@@ -2865,23 +2892,6 @@ static void ironlake_fdi_disable(struct drm_crtc *crtc)
 	udelay(100);
 }
 
-static bool intel_crtc_has_pending_flip(struct drm_crtc *crtc)
-{
-	struct drm_device *dev = crtc->dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	unsigned long flags;
-	bool pending;
-
-	if (atomic_read(&dev_priv->mm.wedged))
-		return false;
-
-	spin_lock_irqsave(&dev->event_lock, flags);
-	pending = to_intel_crtc(crtc)->unpin_work != NULL;
-	spin_unlock_irqrestore(&dev->event_lock, flags);
-
-	return pending;
-}
-
 static void intel_crtc_wait_for_pending_flips(struct drm_crtc *crtc)
 {
 	struct drm_device *dev = crtc->dev;
-- 
1.7.8.6