[Intel-gfx] [PATCH 1/2] drm/i915: Make sure pipe interrupts are processed before turning off power well on BDW+

[ville.syrjala at linux.intel.com]

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

Starting from BDW the DE_PIPE interrupts for pipe B and C belong to the
relevant display power well. So we should make sure we've finished
processing them before turning off the power well.

The pipe interrupts shouldn't really happen at this point anymore since
we've already shut down the planes/pipes/whatnot, but being a bit
paranoid shouldn't hurt.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_irq.c         | 16 ++++++++++++++++
 drivers/gpu/drm/i915/intel_drv.h        |  2 ++
 drivers/gpu/drm/i915/intel_runtime_pm.c | 19 +++++++++++++++++++
 3 files changed, 37 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index d56c261ad867..a9048e1b96e5 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -3366,6 +3366,22 @@ void gen8_irq_power_well_post_enable(struct drm_i915_private *dev_priv,
 	spin_unlock_irq(&dev_priv->irq_lock);
 }
 
+void gen8_irq_power_well_pre_disable(struct drm_i915_private *dev_priv,
+				     unsigned int pipe_mask)
+{
+	spin_lock_irq(&dev_priv->irq_lock);
+	if (pipe_mask & 1 << PIPE_A)
+		GEN8_IRQ_RESET_NDX(DE_PIPE, PIPE_A);
+	if (pipe_mask & 1 << PIPE_B)
+		GEN8_IRQ_RESET_NDX(DE_PIPE, PIPE_B);
+	if (pipe_mask & 1 << PIPE_C)
+		GEN8_IRQ_RESET_NDX(DE_PIPE, PIPE_C);
+	spin_unlock_irq(&dev_priv->irq_lock);
+
+	/* make sure we're done processing display irqs */
+	synchronize_irq(dev_priv->dev->irq);
+}
+
 static void cherryview_irq_preinstall(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 285b0570be9c..2618e3026e8b 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -993,6 +993,8 @@ static inline bool intel_irqs_enabled(struct drm_i915_private *dev_priv)
 int intel_get_crtc_scanline(struct intel_crtc *crtc);
 void gen8_irq_power_well_post_enable(struct drm_i915_private *dev_priv,
 				     unsigned int pipe_mask);
+void gen8_irq_power_well_pre_disable(struct drm_i915_private *dev_priv,
+				     unsigned int pipe_mask);
 
 /* intel_crt.c */
 void intel_crt_init(struct drm_device *dev);
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 59e9222223c9..1afa00855ed8 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -284,6 +284,13 @@ static void hsw_power_well_post_enable(struct drm_i915_private *dev_priv)
 						1 << PIPE_C | 1 << PIPE_B);
 }
 
+static void hsw_power_well_pre_disable(struct drm_i915_private *dev_priv)
+{
+	if (IS_BROADWELL(dev_priv))
+		gen8_irq_power_well_pre_disable(dev_priv,
+						1 << PIPE_C | 1 << PIPE_B);
+}
+
 static void skl_power_well_post_enable(struct drm_i915_private *dev_priv,
 				       struct i915_power_well *power_well)
 {
@@ -309,6 +316,14 @@ static void skl_power_well_post_enable(struct drm_i915_private *dev_priv,
 	}
 }
 
+static void skl_power_well_pre_disable(struct drm_i915_private *dev_priv,
+				       struct i915_power_well *power_well)
+{
+	if (power_well->data == SKL_DISP_PW_2)
+		gen8_irq_power_well_pre_disable(dev_priv,
+						1 << PIPE_C | 1 << PIPE_B);
+}
+
 static void hsw_set_power_well(struct drm_i915_private *dev_priv,
 			       struct i915_power_well *power_well, bool enable)
 {
@@ -334,6 +349,7 @@ static void hsw_set_power_well(struct drm_i915_private *dev_priv,
 
 	} else {
 		if (enable_requested) {
+			hsw_power_well_pre_disable(dev_priv);
 			I915_WRITE(HSW_PWR_WELL_DRIVER, 0);
 			POSTING_READ(HSW_PWR_WELL_DRIVER);
 			DRM_DEBUG_KMS("Requesting to disable the power well\n");
@@ -663,6 +679,9 @@ static void skl_set_power_well(struct drm_i915_private *dev_priv,
 	state_mask = SKL_POWER_WELL_STATE(power_well->data);
 	is_enabled = tmp & state_mask;
 
+	if (!enable && enable_requested)
+		skl_power_well_pre_disable(dev_priv, power_well);
+
 	if (enable) {
 		if (!enable_requested) {
 			WARN((tmp & state_mask) &&
-- 
2.4.10