[Intel-gfx] [PATCH 18/31] drm/i915: Force PSR exit when IRQ_HPD is detected on eDP.

[Rodrigo Vivi]

According to VESA spec: "If a Source device receives and IRQ_HPD
while in a PSR active state, and cannot identify what caused the
IRQ_HPD to be generated, based on Sink device status registers,
the Source device can take implementation-specific action.
One such action can be to exit and then re-enter a PSR active
state."

Since we aren't checking for any sink status registers and we
 aren't looking for any other implementation-specific action,
in case we receive any IRQ_HPD and psr is active let's force
the exit and reschedule it back.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c  |  5 ++++-
 drivers/gpu/drm/i915/intel_drv.h |  1 +
 drivers/gpu/drm/i915/intel_psr.c | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index a421c17..4feb47e 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4851,6 +4851,8 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
 
 	if (intel_dig_port->base.type != INTEL_OUTPUT_EDP)
 		intel_dig_port->base.type = INTEL_OUTPUT_DISPLAYPORT;
+	else
+		intel_psr_irq_hpd(dev);
 
 	if (long_hpd && intel_dig_port->base.type == INTEL_OUTPUT_EDP) {
 		/*
@@ -4859,8 +4861,9 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
 		 * would end up in an endless cycle of
 		 * "vdd off -> long hpd -> vdd on -> detect -> vdd off -> ..."
 		 */
-		DRM_DEBUG_KMS("ignoring long hpd on eDP port %c\n",
+		DRM_DEBUG_KMS("long hpd on eDP port %c\n",
 			      port_name(intel_dig_port->port));
+
 		return IRQ_HANDLED;
 	}
 
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 76e0805..baa560c 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1418,6 +1418,7 @@ void intel_psr_flush(struct drm_device *dev,
 void intel_psr_init(struct drm_device *dev);
 void intel_psr_single_frame_update(struct drm_device *dev,
 				   unsigned frontbuffer_bits);
+void intel_psr_irq_hpd(struct drm_device *dev);
 
 /* intel_runtime_pm.c */
 int intel_power_domains_init(struct drm_i915_private *);
diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
index 4ca682a..c49c6bd 100644
--- a/drivers/gpu/drm/i915/intel_psr.c
+++ b/drivers/gpu/drm/i915/intel_psr.c
@@ -764,6 +764,39 @@ void intel_psr_flush(struct drm_device *dev,
 }
 
 /**
+ * intel_psr_irq_hpd - Let PSR aware of IRQ_HPD
+ * @dev: DRM device
+ *
+ * This function is called when IRQ_HPD is received on eDP.
+ */
+void intel_psr_irq_hpd(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	int delay_ms = HAS_DDI(dev) ? 100 : 500;
+
+	mutex_lock(&dev_priv->psr.lock);
+
+	/*
+	 * According to VESA spec "If a Source device receives and IRQ_HPD
+	 * while in a PSR active state, and cannot identify what caused the
+	 * IRQ_HPD to be generated, based on Sink device status registers,
+	 * the Source device can take implementation-specific action.
+	 * One such action can be to exit and then re-enter a PSR active
+	 * state." Since we aren't checking for any sink status registers
+	 * and we aren't looking for any other implementation-specific
+	 * action, in case we receive any IRQ_HPD and psr is active let's
+	 * force the exit and reschedule it back.
+	 */
+	if (dev_priv->psr.active) {
+		intel_psr_exit(dev);
+		schedule_delayed_work(&dev_priv->psr.work,
+				      msecs_to_jiffies(delay_ms));
+	}
+
+	mutex_unlock(&dev_priv->psr.lock);
+}
+
+/**
  * intel_psr_init - Init basic PSR work and mutex.
  * @dev: DRM device
  *
-- 
2.4.3