[Intel-gfx] [PATCH] drm/i915: Introduce intel_runtime_pm_disable to pair intel_runtime_pm_enable

[Chris Wilson]

Currently, we cancel the extra wakeref we have for !runtime-pm devices
inside power_wells_fini_hw. However, this is not strictly paired with
the acquisition of that wakeref in runtime_pm_enable (as the fini_hw may
be called on errors paths before we even call runtime_pm_enable). Make
the symmetry more explicit and include a check that we do release all of
our rpm wakerefs.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_drv.c         |  8 ++++++--
 drivers/gpu/drm/i915/intel_drv.h        |  1 +
 drivers/gpu/drm/i915/intel_runtime_pm.c | 24 +++++++++++++++---------
 3 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 9dce55182c3a..62ef105a241d 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1281,6 +1281,8 @@ static void i915_driver_register(struct drm_i915_private *dev_priv)
 	 */
 	if (INTEL_INFO(dev_priv)->num_pipes)
 		drm_kms_helper_poll_init(dev);
+
+	intel_runtime_pm_enable(dev_priv);
 }
 
 /**
@@ -1289,6 +1291,8 @@ static void i915_driver_register(struct drm_i915_private *dev_priv)
  */
 static void i915_driver_unregister(struct drm_i915_private *dev_priv)
 {
+	intel_runtime_pm_disable(dev_priv);
+
 	intel_fbdev_unregister(dev_priv);
 	intel_audio_deinit(dev_priv);
 
@@ -1408,8 +1412,6 @@ int i915_driver_load(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	i915_driver_register(dev_priv);
 
-	intel_runtime_pm_enable(dev_priv);
-
 	intel_init_ipc(dev_priv);
 
 	intel_runtime_pm_put(dev_priv);
@@ -1474,6 +1476,8 @@ void i915_driver_unload(struct drm_device *dev)
 	i915_driver_cleanup_mmio(dev_priv);
 
 	intel_display_power_put(dev_priv, POWER_DOMAIN_INIT);
+
+	WARN_ON(atomic_read(&dev_priv->runtime_pm.wakeref_count));
 }
 
 static void i915_driver_release(struct drm_device *dev)
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 0601abb8c71f..dc6c0cec9b36 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1956,6 +1956,7 @@ void intel_power_domains_verify_state(struct drm_i915_private *dev_priv);
 void bxt_display_core_init(struct drm_i915_private *dev_priv, bool resume);
 void bxt_display_core_uninit(struct drm_i915_private *dev_priv);
 void intel_runtime_pm_enable(struct drm_i915_private *dev_priv);
+void intel_runtime_pm_disable(struct drm_i915_private *dev_priv);
 const char *
 intel_display_power_domain_str(enum intel_display_power_domain domain);
 
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index e209edbc561d..b78c3b48aa62 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -3793,8 +3793,6 @@ void intel_power_domains_init_hw(struct drm_i915_private *dev_priv, bool resume)
  */
 void intel_power_domains_fini_hw(struct drm_i915_private *dev_priv)
 {
-	struct device *kdev = &dev_priv->drm.pdev->dev;
-
 	/*
 	 * The i915.ko module is still not prepared to be loaded when
 	 * the power well is not enabled, so just enable it in case
@@ -3809,13 +3807,6 @@ void intel_power_domains_fini_hw(struct drm_i915_private *dev_priv)
 	/* Remove the refcount we took to keep power well support disabled. */
 	if (!i915_modparams.disable_power_well)
 		intel_display_power_put(dev_priv, POWER_DOMAIN_INIT);
-
-	/*
-	 * Remove the refcount we took in intel_runtime_pm_enable() in case
-	 * the platform doesn't support runtime PM.
-	 */
-	if (!HAS_RUNTIME_PM(dev_priv))
-		pm_runtime_put(kdev);
 }
 
 /**
@@ -4074,3 +4065,18 @@ void intel_runtime_pm_enable(struct drm_i915_private *dev_priv)
 	 */
 	pm_runtime_put_autosuspend(kdev);
 }
+
+void intel_runtime_pm_disable(struct drm_i915_private *dev_priv)
+{
+	struct pci_dev *pdev = dev_priv->drm.pdev;
+	struct device *kdev = &pdev->dev;
+
+	pm_runtime_dont_use_autosuspend(kdev);
+
+	/*
+	 * Remove the refcount we took in intel_runtime_pm_enable() in case
+	 * the platform doesn't support runtime PM.
+	 */
+	if (!HAS_RUNTIME_PM(dev_priv))
+		pm_runtime_put(kdev);
+}
-- 
2.18.0