[Intel-gfx] [PATCH 05/10] drm/i915: PSR activate function.

[Rodrigo Vivi]

Let's clear a bit the difference between enable_source and activate
and explain it on comments and docs.

After that we will be able to introduce inactivate/activate VLV+
functions

Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c | 34 +++++++++++++++++++++++++++++++---
 1 file changed, 31 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 335a711..813537a 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -2197,6 +2197,14 @@ static void vlv_edp_psr_enable_sink(struct intel_dp *intel_dp)
 			   DP_PSR_ENABLE);
 }
 
+/**
+ * hsw_edp_psr_enable_sink - Enable PSR on Panel for HSW+.
+ * @intel_dp: DP struct
+ *
+ * This function enable PSR on Panel (Sink) side.
+ * On HSW+ platform when enabling PSR on Panel we need also to setup aux
+ * registers.
+ */
 static void hsw_edp_psr_enable_sink(struct intel_dp *intel_dp)
 {
 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
@@ -2262,6 +2270,16 @@ static void vlv_edp_psr_enable_source(struct intel_dp *intel_dp)
 		   VLV_EDP_PSR_ENABLE);
 }
 
+/**
+ * hsw_edp_psr_enable_source - Enable PSR on Source.
+ * @intel_dp: DP struct
+ *
+ * This function enable PSR on Platform (Source) side.
+ * On HSW+ platform when enabling PSR on Source it also allow Hardware to
+ * immediately transitioning to PSR Entry/Active state as soon as it matches
+ * configure idle_frame count. So this function might be called only when
+ * we really can go to activate state.
+ */
 static void hsw_edp_psr_enable_source(struct intel_dp *intel_dp)
 {
 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
@@ -2336,7 +2354,13 @@ static bool intel_edp_psr_match_conditions(struct intel_dp *intel_dp)
 	return true;
 }
 
-static void intel_edp_psr_do_enable(struct intel_dp *intel_dp)
+/**
+ * intel_edp_psr_activate - Activate PSR
+ * @intel_dp: DP struct
+ *
+ * This function allows PSR to go to Entry/Active state as soon as possible.
+ */
+static void intel_edp_psr_activate(struct intel_dp *intel_dp)
 {
 	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
 	struct drm_device *dev = intel_dig_port->base.base.dev;
@@ -2346,7 +2370,11 @@ static void intel_edp_psr_do_enable(struct intel_dp *intel_dp)
 	WARN_ON(dev_priv->psr.active);
 	lockdep_assert_held(&dev_priv->psr.lock);
 
-	/* Enable/Re-enable PSR on the host */
+	/* Enable/Re-enable PSR on the host
+	 * On HSW/BDW after we enable PSR on source it will activate it
+	 * as soon as it match configure idle_frame count. So
+	 * we just actually enable it here on activation time.
+	 */
 	hsw_edp_psr_enable_source(intel_dp);
 
 	dev_priv->psr.active = true;
@@ -2512,7 +2540,7 @@ static void intel_edp_psr_work(struct work_struct *work)
 	if (dev_priv->psr.busy_frontbuffer_bits)
 		goto unlock;
 
-	intel_edp_psr_do_enable(intel_dp);
+	intel_edp_psr_activate(intel_dp);
 unlock:
 	mutex_unlock(&dev_priv->psr.lock);
 }
-- 
1.9.3