Benchmarking shows that on resume we spend quite a bit of time
just taking and dropping these references, leaving us two options;
either rewriting the code not to take these references more than
once, which would be a rather invasive change since the involved
functions are used from other places, or to optimise
intel_runtime_pm_{get,put}(). This patch does the latter.
Initial benchmarking indicate improvements of a couple
of milliseconds on resume.
Original patch by Chris, with slight fixes by me.
v2: Fix missing return value (Patchwork)
Remove extra atomic_dec() (Chris)
Signed-off-by: David Weinehall <[email protected]>
CC: Chris Wilson <[email protected]>
---
drivers/gpu/drm/i915/intel_runtime_pm.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c
b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 356c662ad453..831fde343d10 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -2632,6 +2632,9 @@ void intel_runtime_pm_get(struct drm_i915_private
*dev_priv)
struct pci_dev *pdev = dev_priv->drm.pdev;
struct device *kdev = &pdev->dev;
+ if (atomic_inc_not_zero(&dev_priv->pm.wakeref_count))
+ return;
+
pm_runtime_get_sync(kdev);
atomic_inc(&dev_priv->pm.wakeref_count);
@@ -2653,6 +2656,9 @@ bool intel_runtime_pm_get_if_in_use(struct
drm_i915_private *dev_priv)
struct pci_dev *pdev = dev_priv->drm.pdev;
struct device *kdev = &pdev->dev;
+ if (atomic_inc_not_zero(&dev_priv->pm.wakeref_count))
+ return true;
+
if (IS_ENABLED(CONFIG_PM)) {
int ret = pm_runtime_get_if_in_use(kdev);
@@ -2695,6 +2701,9 @@ void intel_runtime_pm_get_noresume(struct
drm_i915_private *dev_priv)
struct pci_dev *pdev = dev_priv->drm.pdev;
struct device *kdev = &pdev->dev;
+ if (atomic_inc_not_zero(&dev_priv->pm.wakeref_count))
+ return;
+
assert_rpm_wakelock_held(dev_priv);
pm_runtime_get_noresume(kdev);
@@ -2714,8 +2723,10 @@ void intel_runtime_pm_put(struct drm_i915_private
*dev_priv)
struct pci_dev *pdev = dev_priv->drm.pdev;
struct device *kdev = &pdev->dev;
+ if (!atomic_dec_and_test(&dev_priv->pm.wakeref_count))
+ return;
+
assert_rpm_wakelock_held(dev_priv);
- atomic_dec(&dev_priv->pm.wakeref_count);
pm_runtime_mark_last_busy(kdev);
pm_runtime_put_autosuspend(kdev);
--
2.10.2
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