drm/i915: Fix up PSR frontbuffer tracking

I've tried to split this up, but all the changes are so tightly
related that I didn't find a good way to do this without breaking
bisecting. Essentially this completely changes how psr is glued into
the overall driver, and there's not much you can do to soften such a
paradigm change.

- Use frontbuffer tracking bits stuff to separate disable and
  re-enable.

- Don't re-check everything in the psr work. We have now accurate
  tracking for everything, so no need to check for sprites or tiling
  really. Allows us to ditch tons of locks.

- That in turn allows us to properly cancel the work in the disable
  function - no more deadlocks.

- Add a check for HSW sprites and force a flush. Apparently the
  hardware doesn't forward the flushing when updating the sprite base
  address. We can do the same trick everywhere else we have such
  issues, e.g. on baytrail with ... everything.

- Don't re-enable psr with a delay in psr_exit. It really must be
  turned off forever if we detect a gtt write. At least with the
  current frontbuffer render tracking. Userspace can do a busy ioctl
  call or no-op pageflip to re-enable psr.

- Drop redundant checks for crtc and crtc->active - now that they're
  only called from enable this is guaranteed.

- Fix up the hsw port check. eDP can also happen on port D, but the
  issue is exactly that it doesn't work there. So an || check is
  wrong.

- We still schedule the psr work with a delay. The frontbuffer
  flushing interface mandates that we upload the next full frame, so
  need to wait a bit. Once we have single-shot frame uploads we can do
  better here.

v2: Don't enable psr initially, rely upon the fb flush of the initial
plane setup for that. Gives us more unified code flow and makes the
crtc enable sequence less a special case.

v3: s/psr_exit/psr_invalidate/ for consistency

v4: Fixup whitespace.

v5: Correctly bail out of psr_invalidate/flush when
dev_priv->psr.enabled is NULL. Spotted by Rodrigo.

v6:
- Only schedule work when there's work to do. Fixes WARNINGs reported
  by Rodrigo.
- Comments Chris requested to clarify the code.

v7: Fix conflict on rebase (Rodrigo)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> (v6)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -666,6 +666,7 @@ struct i915_psr {
 	struct intel_dp *enabled;
 	bool active;
 	struct delayed_work work;
+	unsigned busy_frontbuffer_bits;
 };
 
 enum intel_pch {

drivers/gpu/drm/i915/intel_display.c

@@ -8942,7 +8942,7 @@ void intel_fb_obj_invalidate(struct drm_i915_gem_object *obj,
 
 	intel_mark_fb_busy(dev, obj->frontbuffer_bits, ring);
 
-	intel_edp_psr_exit(dev);
+	intel_edp_psr_invalidate(dev, obj->frontbuffer_bits);
 }
 
 /**
@@ -8968,7 +8968,7 @@ void intel_frontbuffer_flush(struct drm_device *dev,
 
 	intel_mark_fb_busy(dev, frontbuffer_bits, NULL);
 
-	intel_edp_psr_exit(dev);
+	intel_edp_psr_flush(dev, frontbuffer_bits);
 }
 
 /**

drivers/gpu/drm/i915/intel_dp.c

@@ -1764,8 +1764,6 @@ static bool intel_edp_psr_match_conditions(struct intel_dp *intel_dp)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct drm_crtc *crtc = dig_port->base.base.crtc;
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
-	struct drm_i915_gem_object *obj = intel_fb_obj(crtc->primary->fb);
-	struct intel_encoder *intel_encoder = &dp_to_dig_port(intel_dp)->base;
 
 	lockdep_assert_held(&dev_priv->psr.lock);
 	lockdep_assert_held(&dev->struct_mutex);
@@ -1779,8 +1777,7 @@ static bool intel_edp_psr_match_conditions(struct intel_dp *intel_dp)
 		return false;
 	}
 
-	if (IS_HASWELL(dev) && (intel_encoder->type != INTEL_OUTPUT_EDP ||
-				dig_port->port != PORT_A)) {
+	if (IS_HASWELL(dev) && dig_port->port != PORT_A) {
 		DRM_DEBUG_KMS("HSW ties PSR to DDI A (eDP)\n");
 		return false;
 	}
@@ -1790,33 +1787,10 @@ static bool intel_edp_psr_match_conditions(struct intel_dp *intel_dp)
 		return false;
 	}
 
-	crtc = dig_port->base.base.crtc;
-	if (crtc == NULL) {
-		DRM_DEBUG_KMS("crtc not active for PSR\n");
-		return false;
-	}
-
-	intel_crtc = to_intel_crtc(crtc);
-	if (!intel_crtc_active(crtc)) {
-		DRM_DEBUG_KMS("crtc not active for PSR\n");
-		return false;
-	}
-
-	if (obj->tiling_mode != I915_TILING_X ||
-	    obj->fence_reg == I915_FENCE_REG_NONE) {
-		DRM_DEBUG_KMS("PSR condition failed: fb not tiled or fenced\n");
-		return false;
-	}
-
 	/* Below limitations aren't valid for Broadwell */
 	if (IS_BROADWELL(dev))
 		goto out;
 
-	if (I915_READ(SPRCTL(intel_crtc->pipe)) & SPRITE_ENABLE) {
-		DRM_DEBUG_KMS("PSR condition failed: Sprite is Enabled\n");
-		return false;
-	}
-
 	if (I915_READ(HSW_STEREO_3D_CTL(intel_crtc->config.cpu_transcoder)) &
 	    S3D_ENABLE) {
 		DRM_DEBUG_KMS("PSR condition failed: Stereo 3D is Enabled\n");
@@ -1849,7 +1823,6 @@ static void intel_edp_psr_do_enable(struct intel_dp *intel_dp)
 	/* Enable PSR on the host */
 	intel_edp_psr_enable_source(intel_dp);
 
-	dev_priv->psr.enabled = intel_dp;
 	dev_priv->psr.active = true;
 }
 
@@ -1875,11 +1848,13 @@ void intel_edp_psr_enable(struct intel_dp *intel_dp)
 		return;
 	}
 
+	dev_priv->psr.busy_frontbuffer_bits = 0;
+
 	/* Setup PSR once */
 	intel_edp_psr_setup(intel_dp);
 
 	if (intel_edp_psr_match_conditions(intel_dp))
-		intel_edp_psr_do_enable(intel_dp);
+		dev_priv->psr.enabled = intel_dp;
 	mutex_unlock(&dev_priv->psr.lock);
 }
 
@@ -1913,42 +1888,39 @@ void intel_edp_psr_disable(struct intel_dp *intel_dp)
 
 	dev_priv->psr.enabled = NULL;
 	mutex_unlock(&dev_priv->psr.lock);
+
+	cancel_delayed_work_sync(&dev_priv->psr.work);
 }
 
 static void intel_edp_psr_work(struct work_struct *work)
 {
 	struct drm_i915_private *dev_priv =
 		container_of(work, typeof(*dev_priv), psr.work.work);
-	struct drm_device *dev = dev_priv->dev;
 	struct intel_dp *intel_dp = dev_priv->psr.enabled;
 
-	drm_modeset_lock_all(dev);
-	mutex_lock(&dev->struct_mutex);
 	mutex_lock(&dev_priv->psr.lock);
 	intel_dp = dev_priv->psr.enabled;
 
 	if (!intel_dp)
 		goto unlock;
 
-	if (intel_edp_psr_match_conditions(intel_dp))
-		intel_edp_psr_do_enable(intel_dp);
+	/*
+	 * The delayed work can race with an invalidate hence we need to
+	 * recheck. Since psr_flush first clears this and then reschedules we
+	 * won't ever miss a flush when bailing out here.
+	 */
+	if (dev_priv->psr.busy_frontbuffer_bits)
+		goto unlock;
+
+	intel_edp_psr_do_enable(intel_dp);
 unlock:
 	mutex_unlock(&dev_priv->psr.lock);
-	mutex_unlock(&dev->struct_mutex);
-	drm_modeset_unlock_all(dev);
 }
 
-void intel_edp_psr_exit(struct drm_device *dev)
+static void intel_edp_psr_do_exit(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
-	if (!HAS_PSR(dev))
-		return;
-
-	if (!dev_priv->psr.enabled)
-		return;
-
-	mutex_lock(&dev_priv->psr.lock);
 	if (dev_priv->psr.active) {
 		u32 val = I915_READ(EDP_PSR_CTL(dev));
 
@@ -1959,8 +1931,68 @@ void intel_edp_psr_exit(struct drm_device *dev)
 		dev_priv->psr.active = false;
 	}
 
-	schedule_delayed_work(&dev_priv->psr.work,
-			      msecs_to_jiffies(100));
+}
+
+void intel_edp_psr_invalidate(struct drm_device *dev,
+			      unsigned frontbuffer_bits)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct drm_crtc *crtc;
+	enum pipe pipe;
+
+	if (!HAS_PSR(dev))
+		return;
+
+	mutex_lock(&dev_priv->psr.lock);
+	if (!dev_priv->psr.enabled) {
+		mutex_unlock(&dev_priv->psr.lock);
+		return;
+	}
+
+	crtc = dp_to_dig_port(dev_priv->psr.enabled)->base.base.crtc;
+	pipe = to_intel_crtc(crtc)->pipe;
+
+	intel_edp_psr_do_exit(dev);
+
+	frontbuffer_bits &= INTEL_FRONTBUFFER_ALL_MASK(pipe);
+
+	dev_priv->psr.busy_frontbuffer_bits |= frontbuffer_bits;
+	mutex_unlock(&dev_priv->psr.lock);
+}
+
+void intel_edp_psr_flush(struct drm_device *dev,
+			 unsigned frontbuffer_bits)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct drm_crtc *crtc;
+	enum pipe pipe;
+
+	if (!HAS_PSR(dev))
+		return;
+
+	mutex_lock(&dev_priv->psr.lock);
+	if (!dev_priv->psr.enabled) {
+		mutex_unlock(&dev_priv->psr.lock);
+		return;
+	}
+
+	crtc = dp_to_dig_port(dev_priv->psr.enabled)->base.base.crtc;
+	pipe = to_intel_crtc(crtc)->pipe;
+	dev_priv->psr.busy_frontbuffer_bits &= ~frontbuffer_bits;
+
+	/*
+	 * On Haswell sprite plane updates don't result in a psr invalidating
+	 * signal in the hardware. Which means we need to manually fake this in
+	 * software for all flushes, not just when we've seen a preceding
+	 * invalidation through frontbuffer rendering.
+	 */
+	if (IS_HASWELL(dev) &&
+	    (frontbuffer_bits & INTEL_FRONTBUFFER_SPRITE(pipe)))
+		intel_edp_psr_do_exit(dev);
+
+	if (!dev_priv->psr.active && !dev_priv->psr.busy_frontbuffer_bits)
+		schedule_delayed_work(&dev_priv->psr.work,
+				      msecs_to_jiffies(100));
 	mutex_unlock(&dev_priv->psr.lock);
 }
 

drivers/gpu/drm/i915/intel_drv.h

@@ -868,7 +868,10 @@ void intel_edp_panel_off(struct intel_dp *intel_dp);
 void intel_edp_psr_enable(struct intel_dp *intel_dp);
 void intel_edp_psr_disable(struct intel_dp *intel_dp);
 void intel_dp_set_drrs_state(struct drm_device *dev, int refresh_rate);
-void intel_edp_psr_exit(struct drm_device *dev);
+void intel_edp_psr_invalidate(struct drm_device *dev,
+			      unsigned frontbuffer_bits);
+void intel_edp_psr_flush(struct drm_device *dev,
+			 unsigned frontbuffer_bits);
 void intel_edp_psr_init(struct drm_device *dev);
 
 /* intel_dsi.c */