[PATCH] drm/i915: Use lockdep to prove runtime_pm correctness

Chris Wilson chris at chris-wilson.co.uk
Fri Jun 22 08:20:42 UTC 2018


Include a lockmap into our runtime_pm so that we can check lock
ordering wrt runtime suspend.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: Imre Deak <imre.deak at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.c         | 6 ++++++
 drivers/gpu/drm/i915/i915_drv.h         | 1 +
 drivers/gpu/drm/i915/intel_runtime_pm.c | 7 +++++++
 3 files changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 0db3c83cce29..3f737a24cc8f 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -873,6 +873,7 @@ static void intel_detect_preproduction_hw(struct drm_i915_private *dev_priv)
 static int i915_driver_init_early(struct drm_i915_private *dev_priv,
 				  const struct pci_device_id *ent)
 {
+	static struct lock_class_key rpm_key;
 	const struct intel_device_info *match_info =
 		(struct intel_device_info *)ent->driver_data;
 	struct intel_device_info *device_info;
@@ -900,6 +901,9 @@ static int i915_driver_init_early(struct drm_i915_private *dev_priv,
 	mutex_init(&dev_priv->wm.wm_mutex);
 	mutex_init(&dev_priv->pps_mutex);
 
+	lockdep_init_map(&dev_priv->runtime_pm.lockmap,
+			 "i915.runtime_pm", &rpm_key, 0);
+
 	i915_memcpy_init_early(dev_priv);
 
 	ret = i915_workqueues_init(dev_priv);
@@ -2594,6 +2598,7 @@ static int intel_runtime_suspend(struct device *kdev)
 	DRM_DEBUG_KMS("Suspending device\n");
 
 	disable_rpm_wakeref_asserts(dev_priv);
+	lock_map_acquire(&dev_priv->runtime_pm.lockmap);
 
 	/*
 	 * We are safe here against re-faults, since the fault handler takes
@@ -2728,6 +2733,7 @@ static int intel_runtime_resume(struct device *kdev)
 
 	intel_enable_ipc(dev_priv);
 
+	lock_map_release(&dev_priv->runtime_pm.lockmap);
 	enable_rpm_wakeref_asserts(dev_priv);
 
 	if (ret)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 6f08ab310118..89dda37d8a17 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1264,6 +1264,7 @@ struct skl_wm_params {
  * For more, read the Documentation/power/runtime_pm.txt.
  */
 struct i915_runtime_pm {
+	struct lockdep_map lockmap;
 	atomic_t wakeref_count;
 	bool suspended;
 	bool irqs_enabled;
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index de3a81034f77..af58b9762117 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -3381,6 +3381,8 @@ void intel_runtime_pm_get(struct drm_i915_private *dev_priv)
 	WARN_ONCE(ret < 0, "pm_runtime_get_sync() failed: %d\n", ret);
 
 	atomic_inc(&dev_priv->runtime_pm.wakeref_count);
+	lock_map_acquire_read(&dev_priv->runtime_pm.lockmap);
+
 	assert_rpm_wakelock_held(dev_priv);
 }
 
@@ -3414,6 +3416,8 @@ bool intel_runtime_pm_get_if_in_use(struct drm_i915_private *dev_priv)
 	}
 
 	atomic_inc(&dev_priv->runtime_pm.wakeref_count);
+	lock_map_acquire_tryread(&dev_priv->runtime_pm.lockmap);
+
 	assert_rpm_wakelock_held(dev_priv);
 
 	return true;
@@ -3445,6 +3449,7 @@ void intel_runtime_pm_get_noresume(struct drm_i915_private *dev_priv)
 	pm_runtime_get_noresume(kdev);
 
 	atomic_inc(&dev_priv->runtime_pm.wakeref_count);
+	lock_map_acquire_read(&dev_priv->runtime_pm.lockmap);
 }
 
 /**
@@ -3461,6 +3466,8 @@ void intel_runtime_pm_put(struct drm_i915_private *dev_priv)
 	struct device *kdev = &pdev->dev;
 
 	assert_rpm_wakelock_held(dev_priv);
+
+	lock_map_release(&dev_priv->runtime_pm.lockmap);
 	atomic_dec(&dev_priv->runtime_pm.wakeref_count);
 
 	pm_runtime_mark_last_busy(kdev);
-- 
2.18.0.rc2



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