[Intel-gfx] [PATCH v3 2/4] 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.

intel_crtc_wait_for_pending_flips() is the current _working_ way to wait
for pending page flips. So use it in intel_pipe_set_base() too. Some
refactoring was necessary to avoid locking struct_mutex twice.

v2: Shuffle the code around so that intel_crtc_wait_for_pending_flips()
    just wraps intel_crtc_wait_for_pending_flips_locked().

v3: Kill leftover wait_event() in intel_finish_fb()

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/intel_display.c |   80 +++++++++++++++++----------------
 1 files changed, 41 insertions(+), 39 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 8c2d810..ea710af 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2238,10 +2238,6 @@ intel_finish_fb(struct drm_framebuffer *old_fb)
 	bool was_interruptible = dev_priv->mm.interruptible;
 	int ret;
 
-	wait_event(dev_priv->pending_flip_queue,
-		   i915_reset_in_progress(&dev_priv->gpu_error) ||
-		   atomic_read(&obj->pending_flip) == 0);
-
 	/* 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
@@ -2284,6 +2280,46 @@ 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 (i915_reset_in_progress(&dev_priv->gpu_error))
+		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 void intel_crtc_wait_for_pending_flips(struct drm_crtc *crtc)
+{
+	struct drm_device *dev = crtc->dev;
+
+	mutex_lock(&dev->struct_mutex);
+	intel_crtc_wait_for_pending_flips_locked(crtc);
+	mutex_unlock(&dev->struct_mutex);
+}
+
 static int
 intel_pipe_set_base(struct drm_crtc *crtc, int x, int y,
 		    struct drm_framebuffer *fb)
@@ -2317,8 +2353,7 @@ 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) {
@@ -2950,39 +2985,6 @@ 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 (i915_reset_in_progress(&dev_priv->gpu_error))
-		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;
-	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));
-
-	mutex_lock(&dev->struct_mutex);
-	intel_finish_fb(crtc->fb);
-	mutex_unlock(&dev->struct_mutex);
-}
-
 static bool ironlake_crtc_driving_pch(struct drm_crtc *crtc)
 {
 	struct drm_device *dev = crtc->dev;
-- 
1.7.8.6