1 files changed, 138 insertions, 11 deletions

diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index ddbdbffe829a..678ed3475d7e 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -470,6 +470,43 @@ static void gen9_set_dc_state_debugmask_memory_up(
 	}
 }
 
+static void gen9_write_dc_state(struct drm_i915_private *dev_priv,
+				u32 state)
+{
+	int rewrites = 0;
+	int rereads = 0;
+	u32 v;
+
+	I915_WRITE(DC_STATE_EN, state);
+
+	/* It has been observed that disabling the dc6 state sometimes
+	 * doesn't stick and dmc keeps returning old value. Make sure
+	 * the write really sticks enough times and also force rewrite until
+	 * we are confident that state is exactly what we want.
+	 */
+	do  {
+		v = I915_READ(DC_STATE_EN);
+
+		if (v != state) {
+			I915_WRITE(DC_STATE_EN, state);
+			rewrites++;
+			rereads = 0;
+		} else if (rereads++ > 5) {
+			break;
+		}
+
+	} while (rewrites < 100);
+
+	if (v != state)
+		DRM_ERROR("Writing dc state to 0x%x failed, now 0x%x\n",
+			  state, v);
+
+	/* Most of the times we need one retry, avoid spam */
+	if (rewrites > 1)
+		DRM_DEBUG_KMS("Rewrote dc state to 0x%x %d times\n",
+			      state, rewrites);
+}
+
 static void gen9_set_dc_state(struct drm_i915_private *dev_priv, uint32_t state)
 {
 	uint32_t val;
@@ -494,10 +531,18 @@ static void gen9_set_dc_state(struct drm_i915_private *dev_priv, uint32_t state)
 	val = I915_READ(DC_STATE_EN);
 	DRM_DEBUG_KMS("Setting DC state from %02x to %02x\n",
 		      val & mask, state);
+
+	/* Check if DMC is ignoring our DC state requests */
+	if ((val & mask) != dev_priv->csr.dc_state)
+		DRM_ERROR("DC state mismatch (0x%x -> 0x%x)\n",
+			  dev_priv->csr.dc_state, val & mask);
+
 	val &= ~mask;
 	val |= state;
-	I915_WRITE(DC_STATE_EN, val);
-	POSTING_READ(DC_STATE_EN);
+
+	gen9_write_dc_state(dev_priv, val);
+
+	dev_priv->csr.dc_state = val & mask;
 }
 
 void bxt_enable_dc9(struct drm_i915_private *dev_priv)
@@ -1442,6 +1487,22 @@ static void chv_pipe_power_well_disable(struct drm_i915_private *dev_priv,
 	chv_set_pipe_power_well(dev_priv, power_well, false);
 }
 
+static void
+__intel_display_power_get_domain(struct drm_i915_private *dev_priv,
+				 enum intel_display_power_domain domain)
+{
+	struct i915_power_domains *power_domains = &dev_priv->power_domains;
+	struct i915_power_well *power_well;
+	int i;
+
+	for_each_power_well(i, power_well, BIT(domain), power_domains) {
+		if (!power_well->count++)
+			intel_power_well_enable(dev_priv, power_well);
+	}
+
+	power_domains->domain_use_count[domain]++;
+}
+
 /**
  * intel_display_power_get - grab a power domain reference
  * @dev_priv: i915 device instance
@@ -1457,24 +1518,53 @@ static void chv_pipe_power_well_disable(struct drm_i915_private *dev_priv,
 void intel_display_power_get(struct drm_i915_private *dev_priv,
 			     enum intel_display_power_domain domain)
 {
-	struct i915_power_domains *power_domains;
-	struct i915_power_well *power_well;
-	int i;
+	struct i915_power_domains *power_domains = &dev_priv->power_domains;
 
 	intel_runtime_pm_get(dev_priv);
 
-	power_domains = &dev_priv->power_domains;
+	mutex_lock(&power_domains->lock);
+
+	__intel_display_power_get_domain(dev_priv, domain);
+
+	mutex_unlock(&power_domains->lock);
+}
+
+/**
+ * intel_display_power_get_if_enabled - grab a reference for an enabled display power domain
+ * @dev_priv: i915 device instance
+ * @domain: power domain to reference
+ *
+ * This function grabs a power domain reference for @domain and ensures that the
+ * power domain and all its parents are powered up. Therefore users should only
+ * grab a reference to the innermost power domain they need.
+ *
+ * Any power domain reference obtained by this function must have a symmetric
+ * call to intel_display_power_put() to release the reference again.
+ */
+bool intel_display_power_get_if_enabled(struct drm_i915_private *dev_priv,
+					enum intel_display_power_domain domain)
+{
+	struct i915_power_domains *power_domains = &dev_priv->power_domains;
+	bool is_enabled;
+
+	if (!intel_runtime_pm_get_if_in_use(dev_priv))
+		return false;
 
 	mutex_lock(&power_domains->lock);
 
-	for_each_power_well(i, power_well, BIT(domain), power_domains) {
-		if (!power_well->count++)
-			intel_power_well_enable(dev_priv, power_well);
+	if (__intel_display_power_is_enabled(dev_priv, domain)) {
+		__intel_display_power_get_domain(dev_priv, domain);
+		is_enabled = true;
+	} else {
+		is_enabled = false;
 	}
 
-	power_domains->domain_use_count[domain]++;
-
 	mutex_unlock(&power_domains->lock);
+
+	if (!is_enabled)
+		intel_runtime_pm_put(dev_priv);
+
+	return is_enabled;
 }
 
 /**
@@ -2246,6 +2336,43 @@ void intel_runtime_pm_get(struct drm_i915_private *dev_priv)
 }
 
 /**
+ * intel_runtime_pm_get_if_in_use - grab a runtime pm reference if device in use
+ * @dev_priv: i915 device instance
+ *
+ * This function grabs a device-level runtime pm reference if the device is
+ * already in use and ensures that it is powered up.
+ *
+ * Any runtime pm reference obtained by this function must have a symmetric
+ * call to intel_runtime_pm_put() to release the reference again.
+ */
+bool intel_runtime_pm_get_if_in_use(struct drm_i915_private *dev_priv)
+{
+	struct drm_device *dev = dev_priv->dev;
+	struct device *device = &dev->pdev->dev;
+	int ret;
+
+	if (!IS_ENABLED(CONFIG_PM))
+		return true;
+
+	ret = pm_runtime_get_if_in_use(device);
+
+	/*
+	 * In cases runtime PM is disabled by the RPM core and we get an
+	 * -EINVAL return value we are not supposed to call this function,
+	 * since the power state is undefined. This applies atm to the
+	 * late/early system suspend/resume handlers.
+	 */
+	WARN_ON_ONCE(ret < 0);
+	if (ret <= 0)
+		return false;
+
+	atomic_inc(&dev_priv->pm.wakeref_count);
+	assert_rpm_wakelock_held(dev_priv);
+
+	return true;
+}
+
+/**
  * intel_runtime_pm_get_noresume - grab a runtime pm reference
  * @dev_priv: i915 device instance
  *