[Intel-gfx] [PATCH 2/4] drm/i915: Disable PSR when a PSR aux error happen

[José Roberto de Souza]

While PSR is active hardware will do aux transactions by it self to
wakeup sink to receive a new frame when necessary. If that
transaction is not acked by sink, hardware will trigger this
interruption.

So let's disable PSR as it is a hint that there is problem with this
sink.

The removed FIXME was asking to manually train the link but we don't
need to do that as by spec sink should do a short pulse when it is
out of sync with source, we just need to make sure it is awaken and
the SDP header with PSR disable will trigger this condition.

Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h  |  1 +
 drivers/gpu/drm/i915/intel_psr.c | 39 ++++++++++++++++++++++++++++----
 2 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 794a8a03c7e6..efbebe1c2ba3 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -638,6 +638,7 @@ struct i915_psr {
 	u8 sink_sync_latency;
 	ktime_t last_entry_attempt;
 	ktime_t last_exit;
+	u32 irq_aux_error;
 };
 
 enum intel_pch {
diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
index cd9a60d1efa1..74090fffea23 100644
--- a/drivers/gpu/drm/i915/intel_psr.c
+++ b/drivers/gpu/drm/i915/intel_psr.c
@@ -159,10 +159,16 @@ void intel_psr_irq_handler(struct drm_i915_private *dev_priv, u32 psr_iir)
 			       BIT(TRANSCODER_C);
 
 	for_each_cpu_transcoder_masked(dev_priv, cpu_transcoder, transcoders) {
-		/* FIXME: Exit PSR and link train manually when this happens. */
-		if (psr_iir & EDP_PSR_ERROR(cpu_transcoder))
-			DRM_DEBUG_KMS("[transcoder %s] PSR aux error\n",
-				      transcoder_name(cpu_transcoder));
+		if (psr_iir & EDP_PSR_ERROR(cpu_transcoder)) {
+			DRM_WARN("[transcoder %s] PSR aux error\n",
+				 transcoder_name(cpu_transcoder));
+
+			spin_lock(&dev_priv->irq_lock);
+			dev_priv->psr.irq_aux_error |= BIT(cpu_transcoder);
+			spin_unlock(&dev_priv->irq_lock);
+
+			schedule_work(&dev_priv->psr.work);
+		}
 
 		if (psr_iir & EDP_PSR_PRE_ENTRY(cpu_transcoder)) {
 			dev_priv->psr.last_entry_attempt = time_ns;
@@ -891,11 +897,36 @@ int intel_psr_set_debugfs_mode(struct drm_i915_private *dev_priv,
 	return ret;
 }
 
+static void intel_psr_handle_irq(struct drm_i915_private *dev_priv)
+{
+	struct i915_psr *psr = &dev_priv->psr;
+	u32 irq_aux_error;
+
+	spin_lock_irq(&dev_priv->irq_lock);
+	irq_aux_error = psr->irq_aux_error;
+	psr->irq_aux_error = 0;
+	spin_unlock_irq(&dev_priv->irq_lock);
+
+	/* right now PSR is only enabled in eDP */
+	WARN_ON(irq_aux_error & ~BIT(TRANSCODER_EDP));
+
+	mutex_lock(&psr->lock);
+
+	intel_psr_disable_locked(psr->dp);
+	/* let's make sure that sink is awaken */
+	drm_dp_dpcd_writeb(&psr->dp->aux, DP_SET_POWER, DP_SET_POWER_D0);
+
+	mutex_unlock(&dev_priv->psr.lock);
+}
+
 static void intel_psr_work(struct work_struct *work)
 {
 	struct drm_i915_private *dev_priv =
 		container_of(work, typeof(*dev_priv), psr.work);
 
+	if (READ_ONCE(dev_priv->psr.irq_aux_error))
+		intel_psr_handle_irq(dev_priv);
+
 	mutex_lock(&dev_priv->psr.lock);
 
 	if (!dev_priv->psr.enabled)
-- 
2.19.0