[Intel-gfx] [PATCH] drm/i915: Use a high priority wq for nonblocking plane updates

[Ville Syrjala]

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

system_unbound_wq can't keep up sometimes and we get dropped frames.
Switch to a high priority variant.

Reported-by: Heinrich Fink <heinrich.fink at daqri.com>
Tested-by: Heinrich Fink <heinrich.fink at daqri.com>
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_display.c | 6 +++++-
 drivers/gpu/drm/i915/i915_drv.h              | 2 ++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 3b5275ab66cf..2668744007b3 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -14272,7 +14272,7 @@ static int intel_atomic_commit(struct drm_device *dev,
 	if (nonblock && state->modeset) {
 		queue_work(dev_priv->modeset_wq, &state->base.commit_work);
 	} else if (nonblock) {
-		queue_work(system_unbound_wq, &state->base.commit_work);
+		queue_work(dev_priv->flip_wq, &state->base.commit_work);
 	} else {
 		if (state->modeset)
 			flush_workqueue(dev_priv->modeset_wq);
@@ -16181,6 +16181,8 @@ int intel_modeset_init(struct drm_device *dev)
 	int ret;
 
 	dev_priv->modeset_wq = alloc_ordered_workqueue("i915_modeset", 0);
+	dev_priv->flip_wq = alloc_workqueue("i915_flip", WQ_HIGHPRI |
+					    WQ_UNBOUND, WQ_UNBOUND_MAX_ACTIVE);
 
 	drm_mode_config_init(dev);
 
@@ -17139,6 +17141,7 @@ void intel_modeset_driver_remove(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = to_i915(dev);
 
+	flush_workqueue(dev_priv->flip_wq);
 	flush_workqueue(dev_priv->modeset_wq);
 
 	flush_work(&dev_priv->atomic_helper.free_work);
@@ -17175,6 +17178,7 @@ void intel_modeset_driver_remove(struct drm_device *dev)
 
 	intel_gmbus_teardown(dev_priv);
 
+	destroy_workqueue(dev_priv->flip_wq);
 	destroy_workqueue(dev_priv->modeset_wq);
 
 	intel_fbc_cleanup_cfb(dev_priv);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index e289b4ffd34b..d4177ca8ffc8 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1434,6 +1434,8 @@ struct drm_i915_private {
 
 	/* ordered wq for modesets */
 	struct workqueue_struct *modeset_wq;
+	/* unbound hipri wq for page flips/plane updates */
+	struct workqueue_struct *flip_wq;
 
 	/* Display functions */
 	struct drm_i915_display_funcs display;
-- 
2.21.0