[Intel-gfx] [RFC 2/6] drm/i915: Initialize DRRS delayed work

[Vandana Kannan]

Initializing DRRS work to program lower refresh rate.

Signed-off-by: Vandana Kannan <vandana.kannan at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c | 36 ++++++++++++++++++++++++++++--------
 1 file changed, 28 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index be9d90d..1ceec86 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4868,19 +4868,37 @@ static void intel_dp_set_drrs_state(struct drm_device *dev, int refresh_rate)
 		I915_WRITE(reg, val);
 	}
 
+	dev_priv->drrs.refresh_rate_type = index;
+
+	DRM_DEBUG_KMS("eDP Refresh Rate set to : %dHz\n", refresh_rate);
+}
+
+static void intel_edp_drrs_work(struct work_struct *work)
+{
+	struct drm_i915_private *dev_priv =
+		container_of(work, typeof(*dev_priv), drrs.work.work);
+	struct intel_dp *intel_dp = dev_priv->drrs.dp;
+
+	mutex_lock(&dev_priv->drrs.mutex);
+
+	if (!intel_dp)
+		goto unlock;
+
 	/*
-	 * mutex taken to ensure that there is no race between differnt
-	 * drrs calls trying to update refresh rate. This scenario may occur
-	 * in future when idleness detection based DRRS in kernel and
-	 * possible calls from user space to set differnt RR are made.
+	 * 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.
 	 */
-	mutex_lock(&dev_priv->drrs.mutex);
+	if (dev_priv->drrs.busy_frontbuffer_bits)
+		goto unlock;
 
-	dev_priv->drrs.refresh_rate_type = index;
+	if (dev_priv->drrs.refresh_rate_type != DRRS_LOW_RR)
+		intel_dp_set_drrs_state(dev_priv->dev,
+			intel_dp->attached_connector->panel.
+			downclock_mode->vrefresh);
 
+unlock:
 	mutex_unlock(&dev_priv->drrs.mutex);
-
-	DRM_DEBUG_KMS("eDP Refresh Rate set to : %dHz\n", refresh_rate);
 }
 
 static struct drm_display_mode *
@@ -4910,6 +4928,8 @@ intel_dp_drrs_init(struct intel_connector *intel_connector,
 		return NULL;
 	}
 
+	INIT_DELAYED_WORK(&dev_priv->drrs.work, intel_edp_drrs_work);
+
 	mutex_init(&dev_priv->drrs.mutex);
 
 	dev_priv->drrs.type = dev_priv->vbt.drrs_type;
-- 
2.0.1