[PATCH 02/11] drm/i915: Add support for tracking wakerefs w/o power-on guarantee

Imre Deak imre.deak at intel.com
Wed May 1 08:12:26 UTC 2019


It's useful to track runtime PM refs that don't guarantee a device
power-on state to the rest of the driver. For instance when holding a
ref for disabling runtime PM itself, or holding a reference that will be
put asynchronously, during which normal users without their own
reference shouldn't access the HW. For this we can track all references
with a separate wakeref_track_count and references guaranteeing a
power-on state with the current wakeref_count.

Follow-up patches will make use of the API added here, so add a
__used__ attribute quirk to keep git bisect working.

No functional changes.

Signed-off-by: Imre Deak <imre.deak at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h         |  1 +
 drivers/gpu/drm/i915/intel_runtime_pm.c | 92 ++++++++++++++++++++-----
 2 files changed, 74 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 886a30243fe3..cd420791b1aa 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1177,6 +1177,7 @@ struct skl_wm_params {
  */
 struct i915_runtime_pm {
 	atomic_t wakeref_count;
+	atomic_t wakeref_track_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 a0ea38319841..1f4f9e69fa1d 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -100,18 +100,17 @@ static void init_intel_runtime_pm_wakeref(struct drm_i915_private *i915)
 	struct i915_runtime_pm *rpm = &i915->runtime_pm;
 
 	spin_lock_init(&rpm->debug.lock);
+	atomic_set(&rpm->wakeref_track_count, 0);
 }
 
 static noinline depot_stack_handle_t
-track_intel_runtime_pm_wakeref(struct drm_i915_private *i915)
+track_intel_runtime_pm_wakeref_raw(struct drm_i915_private *i915)
 {
 	struct i915_runtime_pm *rpm = &i915->runtime_pm;
 	depot_stack_handle_t stack, *stacks;
 	unsigned long flags;
 
-	atomic_inc(&rpm->wakeref_count);
-	assert_rpm_wakelock_held(i915);
-
+	atomic_inc(&rpm->wakeref_track_count);
 	if (!HAS_RUNTIME_PM(i915))
 		return -1;
 
@@ -139,6 +138,15 @@ track_intel_runtime_pm_wakeref(struct drm_i915_private *i915)
 	return stack;
 }
 
+static noinline depot_stack_handle_t
+track_intel_runtime_pm_wakeref(struct drm_i915_private *i915)
+{
+	atomic_inc(&i915->runtime_pm.wakeref_count);
+	assert_rpm_wakelock_held(i915);
+
+	return track_intel_runtime_pm_wakeref_raw(i915);
+}
+
 static void cancel_intel_runtime_pm_wakeref(struct drm_i915_private *i915,
 					    depot_stack_handle_t stack)
 {
@@ -163,7 +171,7 @@ static void cancel_intel_runtime_pm_wakeref(struct drm_i915_private *i915,
 
 	if (WARN(!found,
 		 "Unmatched wakeref (tracking %lu), count %u\n",
-		 rpm->debug.count, atomic_read(&rpm->wakeref_count))) {
+		 rpm->debug.count, atomic_read(&rpm->wakeref_track_count))) {
 		char *buf;
 
 		buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN);
@@ -235,15 +243,14 @@ __print_intel_runtime_pm_wakeref(struct drm_printer *p,
 }
 
 static noinline void
-untrack_intel_runtime_pm_wakeref(struct drm_i915_private *i915)
+untrack_intel_runtime_pm_wakeref_raw(struct drm_i915_private *i915)
 {
 	struct i915_runtime_pm *rpm = &i915->runtime_pm;
 	struct intel_runtime_pm_debug dbg = {};
 	struct drm_printer p;
 	unsigned long flags;
 
-	assert_rpm_wakelock_held(i915);
-	if (atomic_dec_and_lock_irqsave(&rpm->wakeref_count,
+	if (atomic_dec_and_lock_irqsave(&rpm->wakeref_track_count,
 					&rpm->debug.lock,
 					flags)) {
 		dbg = rpm->debug;
@@ -263,6 +270,15 @@ untrack_intel_runtime_pm_wakeref(struct drm_i915_private *i915)
 	kfree(dbg.owners);
 }
 
+static noinline void
+untrack_intel_runtime_pm_wakeref(struct drm_i915_private *i915)
+{
+	assert_rpm_wakelock_held(i915);
+	atomic_dec(&i915->runtime_pm.wakeref_count);
+
+	untrack_intel_runtime_pm_wakeref_raw(i915);
+}
+
 void print_intel_runtime_pm_wakeref(struct drm_i915_private *i915,
 				    struct drm_printer *p)
 {
@@ -4347,7 +4363,7 @@ static void intel_power_domains_verify_state(struct drm_i915_private *i915)
  *
  * Returns: the wakeref cookie to pass to intel_runtime_pm_put()
  */
-intel_wakeref_t intel_runtime_pm_get(struct drm_i915_private *i915)
+static void __intel_runtime_pm_get(struct drm_i915_private *i915)
 {
 	struct pci_dev *pdev = i915->drm.pdev;
 	struct device *kdev = &pdev->dev;
@@ -4355,10 +4371,23 @@ intel_wakeref_t intel_runtime_pm_get(struct drm_i915_private *i915)
 
 	ret = pm_runtime_get_sync(kdev);
 	WARN_ONCE(ret < 0, "pm_runtime_get_sync() failed: %d\n", ret);
+}
+
+intel_wakeref_t intel_runtime_pm_get(struct drm_i915_private *i915)
+{
+	__intel_runtime_pm_get(i915);
 
 	return track_intel_runtime_pm_wakeref(i915);
 }
 
+__attribute__((__used__))
+static intel_wakeref_t intel_runtime_pm_get_raw(struct drm_i915_private *i915)
+{
+	__intel_runtime_pm_get(i915);
+
+	return track_intel_runtime_pm_wakeref_raw(i915);
+}
+
 /**
  * intel_runtime_pm_get_if_in_use - grab a runtime pm reference if device in use
  * @i915: i915 device instance
@@ -4430,15 +4459,25 @@ intel_wakeref_t intel_runtime_pm_get_noresume(struct drm_i915_private *i915)
  * intel_runtime_pm_get() and might power down the corresponding
  * hardware block right away if this is the last reference.
  */
+static void __intel_runtime_pm_put_unchecked(struct drm_i915_private *i915)
+{
+	struct pci_dev *pdev = i915->drm.pdev;
+	struct device *kdev = &pdev->dev;
+
+	pm_runtime_mark_last_busy(kdev);
+	pm_runtime_put_autosuspend(kdev);
+}
+
+static void intel_runtime_pm_put_unchecked_raw(struct drm_i915_private *i915)
+{
+	untrack_intel_runtime_pm_wakeref_raw(i915);
+	__intel_runtime_pm_put_unchecked(i915);
+}
+
 void intel_runtime_pm_put_unchecked(struct drm_i915_private *i915)
 {
-	struct pci_dev *pdev = i915->drm.pdev;
-	struct device *kdev = &pdev->dev;
-
 	untrack_intel_runtime_pm_wakeref(i915);
-
-	pm_runtime_mark_last_busy(kdev);
-	pm_runtime_put_autosuspend(kdev);
+	__intel_runtime_pm_put_unchecked(i915);
 }
 
 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
@@ -4447,6 +4486,21 @@ void intel_runtime_pm_put(struct drm_i915_private *i915, intel_wakeref_t wref)
 	cancel_intel_runtime_pm_wakeref(i915, wref);
 	intel_runtime_pm_put_unchecked(i915);
 }
+
+__attribute__((__used__))
+static void intel_runtime_pm_put_raw(struct drm_i915_private *i915,
+				     intel_wakeref_t wref)
+{
+	cancel_intel_runtime_pm_wakeref(i915, wref);
+	intel_runtime_pm_put_unchecked_raw(i915);
+}
+#else
+__attribute__((__used__))
+static void intel_runtime_pm_put_raw(struct drm_i915_private *i915,
+				     intel_wakeref_t wref)
+{
+	intel_runtime_pm_put_unchecked_raw(i915);
+}
 #endif
 
 /**
@@ -4521,12 +4575,12 @@ void intel_runtime_pm_cleanup(struct drm_i915_private *i915)
 	struct i915_runtime_pm *rpm = &i915->runtime_pm;
 	int count;
 
-	count = atomic_xchg(&rpm->wakeref_count, 1); /* force printing */
+	count = atomic_xchg(&rpm->wakeref_track_count, 1); /* force printing */
 	WARN(count,
-	     "i915->runtime_pm.wakeref_count=%d on cleanup\n",
+	     "i915->runtime_pm.wakeref_track_count=%d on cleanup\n",
 	     count);
-	untrack_intel_runtime_pm_wakeref(i915);
-	atomic_add(count, &rpm->wakeref_count);
+	untrack_intel_runtime_pm_wakeref_raw(i915);
+	atomic_add(count, &rpm->wakeref_track_count);
 }
 
 void intel_runtime_pm_init_early(struct drm_i915_private *i915)
-- 
2.17.1



More information about the Intel-gfx-trybot mailing list