Everytime we take a wakeref, record the stack trace of where it was
taken; clearing the set if we ever drop back to no owners. For debugging
a rpm leak, we can look at all the current wakerefs and check if they
have a matching rpm_put.
Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/Kconfig.debug | 13 ++
drivers/gpu/drm/i915/i915_drv.c | 10 +-
drivers/gpu/drm/i915/i915_drv.h | 7 +
drivers/gpu/drm/i915/intel_drv.h | 32 +--
drivers/gpu/drm/i915/intel_runtime_pm.c | 219 +++++++++++++++---
.../gpu/drm/i915/selftests/mock_gem_device.c | 8 +-
6 files changed, 241 insertions(+), 48 deletions(-)
diff --git a/drivers/gpu/drm/i915/Kconfig.debug
b/drivers/gpu/drm/i915/Kconfig.debug
index 459f8f88a34c..ed572a454e01 100644
--- a/drivers/gpu/drm/i915/Kconfig.debug
+++ b/drivers/gpu/drm/i915/Kconfig.debug
@@ -39,6 +39,19 @@ config DRM_I915_DEBUG
If in doubt, say "N".
+config DRM_I915_DEBUG_RPM
+ bool "Insert extra checks into the runtime pm internals"
+ depends on DRM_I915
+ default n
+ select STACKDEPOT
+ help
+ Enable extra sanity checks (including BUGs) along the runtime pm
+ paths that may slow the system down and if hit hang the machine.
+
+ Recommended for driver developers only.
+
+ If in doubt, say "N".
+
config DRM_I915_DEBUG_GEM
bool "Insert extra checks into the GEM internals"
default n
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index bc072bef8f0a..b2b3c85299e6 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1315,6 +1315,8 @@ static void i915_welcome_messages(struct drm_i915_private
*dev_priv)
DRM_INFO("DRM_I915_DEBUG enabled\n");
if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
DRM_INFO("DRM_I915_DEBUG_GEM enabled\n");
+ if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_RPM))
+ DRM_INFO("DRM_I915_DEBUG_RPM enabled\n");
}
static struct drm_i915_private *
@@ -1376,6 +1378,8 @@ int i915_driver_load(struct pci_dev *pdev, const struct
pci_device_id *ent)
if (!dev_priv)
return -ENOMEM;
+ intel_runtime_pm_init_early(dev_priv);
+
intel_runtime_pm_get(dev_priv);
intel_runtime_pm_enable(dev_priv);
@@ -1478,7 +1482,7 @@ void i915_driver_unload(struct drm_device *dev)
intel_runtime_pm_disable(dev_priv);
intel_display_power_put(dev_priv, POWER_DOMAIN_INIT);
- WARN_ON(atomic_read(&dev_priv->runtime_pm.wakeref_count));
+ intel_runtime_pm_cleanup(dev_priv);
}
static void i915_driver_release(struct drm_device *dev)
@@ -1686,6 +1690,8 @@ static int i915_drm_suspend_late(struct drm_device *dev,
bool hibernation)
out:
enable_rpm_wakeref_asserts(dev_priv);
+ if (!dev_priv->uncore.user_forcewake.count)
+ intel_runtime_pm_cleanup(dev_priv);
return ret;
}
@@ -2646,7 +2652,7 @@ static int intel_runtime_suspend(struct device *kdev)
}
enable_rpm_wakeref_asserts(dev_priv);
- WARN_ON_ONCE(atomic_read(&dev_priv->runtime_pm.wakeref_count));
+ intel_runtime_pm_cleanup(dev_priv);
if (intel_uncore_arm_unclaimed_mmio_detection(dev_priv))
DRM_ERROR("Unclaimed access detected prior to suspending\n");
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 5fa13887b911..6f2b81f135cf 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -45,6 +45,7 @@
#include <linux/pm_qos.h>
#include <linux/reservation.h>
#include <linux/shmem_fs.h>
+#include <linux/stackdepot.h>
#include <drm/drmP.h>
#include <drm/intel-gtt.h>
@@ -1287,6 +1288,12 @@ struct i915_runtime_pm {
atomic_t wakeref_count;
bool suspended;
bool irqs_enabled;
+
+#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RPM)
+ spinlock_t debug_lock;
+ depot_stack_handle_t *debug_owners;
+ unsigned long debug_count;
+#endif
};
enum intel_pipe_crc_source {
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 364fc2504fa4..5942593f1732 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1950,6 +1950,7 @@ void intel_psr_short_pulse(struct intel_dp *intel_dp);
int intel_psr_wait_for_idle(const struct intel_crtc_state *new_crtc_state);
/* intel_runtime_pm.c */
+void intel_runtime_pm_init_early(struct drm_i915_private *dev_priv);
int intel_power_domains_init(struct drm_i915_private *);
void intel_power_domains_cleanup(struct drm_i915_private *dev_priv);
void intel_power_domains_init_hw(struct drm_i915_private *dev_priv, bool
resume);
@@ -1960,6 +1961,7 @@ 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);
+void intel_runtime_pm_cleanup(struct drm_i915_private *dev_priv);
const char *
intel_display_power_domain_str(enum intel_display_power_domain domain);
@@ -1977,23 +1979,23 @@ void icl_dbuf_slices_update(struct drm_i915_private
*dev_priv,
u8 req_slices);
static inline void
-assert_rpm_device_not_suspended(struct drm_i915_private *dev_priv)
+assert_rpm_device_not_suspended(struct drm_i915_private *i915)
{
- WARN_ONCE(dev_priv->runtime_pm.suspended,
+ WARN_ONCE(i915->runtime_pm.suspended,
"Device suspended during HW access\n");
}
static inline void
-assert_rpm_wakelock_held(struct drm_i915_private *dev_priv)
+assert_rpm_wakelock_held(struct drm_i915_private *i915)
{
- assert_rpm_device_not_suspended(dev_priv);
- WARN_ONCE(!atomic_read(&dev_priv->runtime_pm.wakeref_count),
+ assert_rpm_device_not_suspended(i915);
+ WARN_ONCE(!atomic_read(&i915->runtime_pm.wakeref_count),
"RPM wakelock ref not held during HW access");
}
/**
* disable_rpm_wakeref_asserts - disable the RPM assert checks
- * @dev_priv: i915 device instance
+ * @i915: i915 device instance
*
* This function disable asserts that check if we hold an RPM wakelock
* reference, while keeping the device-not-suspended checks still enabled.
@@ -2010,14 +2012,14 @@ assert_rpm_wakelock_held(struct drm_i915_private
*dev_priv)
* enable_rpm_wakeref_asserts().
*/
static inline void
-disable_rpm_wakeref_asserts(struct drm_i915_private *dev_priv)
+disable_rpm_wakeref_asserts(struct drm_i915_private *i915)
{
- atomic_inc(&dev_priv->runtime_pm.wakeref_count);
+ atomic_inc(&i915->runtime_pm.wakeref_count);
}
/**
* enable_rpm_wakeref_asserts - re-enable the RPM assert checks
- * @dev_priv: i915 device instance
+ * @i915: i915 device instance
*
* This function re-enables the RPM assert checks after disabling them with
* disable_rpm_wakeref_asserts. It's meant to be used only in special
@@ -2027,15 +2029,15 @@ disable_rpm_wakeref_asserts(struct drm_i915_private
*dev_priv)
* disable_rpm_wakeref_asserts().
*/
static inline void
-enable_rpm_wakeref_asserts(struct drm_i915_private *dev_priv)
+enable_rpm_wakeref_asserts(struct drm_i915_private *i915)
{
- atomic_dec(&dev_priv->runtime_pm.wakeref_count);
+ atomic_dec(&i915->runtime_pm.wakeref_count);
}
-void intel_runtime_pm_get(struct drm_i915_private *dev_priv);
-bool intel_runtime_pm_get_if_in_use(struct drm_i915_private *dev_priv);
-void intel_runtime_pm_get_noresume(struct drm_i915_private *dev_priv);
-void intel_runtime_pm_put(struct drm_i915_private *dev_priv);
+void intel_runtime_pm_get(struct drm_i915_private *i915);
+bool intel_runtime_pm_get_if_in_use(struct drm_i915_private *i915);
+void intel_runtime_pm_get_noresume(struct drm_i915_private *i915);
+void intel_runtime_pm_put(struct drm_i915_private *i915);
void intel_display_set_init_power(struct drm_i915_private *dev, bool enable);
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c
b/drivers/gpu/drm/i915/intel_runtime_pm.c
index c0983f0e46ac..425d885f84b6 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -49,6 +49,143 @@
* present for a given platform.
*/
+#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RPM)
+
+#include <linux/sort.h>
+
+#define STACKDEPTH 8
+
+static void init_intel_runtime_pm_wakeref(struct drm_i915_private *i915)
+{
+ spin_lock_init(&i915->runtime_pm.debug_lock);
+}
+
+static noinline void
+track_intel_runtime_pm_wakeref(struct drm_i915_private *i915)
+{
+ struct i915_runtime_pm *rpm = &i915->runtime_pm;
+ unsigned long entries[STACKDEPTH];
+ struct stack_trace trace = {
+ .entries = entries,
+ .max_entries = ARRAY_SIZE(entries),
+ .skip = 1
+ };
+ unsigned long flags;
+ depot_stack_handle_t stack, *stacks;
+
+ if (!HAS_RUNTIME_PM(i915))
+ return;
+
+ save_stack_trace(&trace);
+ if (trace.nr_entries &&
+ trace.entries[trace.nr_entries - 1] == ULONG_MAX)
+ trace.nr_entries--;
+
+ stack = depot_save_stack(&trace, GFP_NOWAIT | __GFP_NOWARN);
+ if (!stack)
+ return;
+
+ spin_lock_irqsave(&rpm->debug_lock, flags);
+ stacks = krealloc(rpm->debug_owners,
+ (rpm->debug_count + 1) * sizeof(*stacks),
+ GFP_NOWAIT | __GFP_NOWARN);
+ if (stacks) {
+ stacks[rpm->debug_count++] = stack;
+ rpm->debug_owners = stacks;
+ }
+ spin_unlock_irqrestore(&rpm->debug_lock, flags);
+}
+
+static void untrack_intel_runtime_pm_wakeref(struct drm_i915_private *i915)
+{
+ struct i915_runtime_pm *rpm = &i915->runtime_pm;
+ depot_stack_handle_t *stacks;
+ unsigned long flags;
+
+ spin_lock_irqsave(&rpm->debug_lock, flags);
+ stacks = fetch_and_zero(&rpm->debug_owners);
+ rpm->debug_count = 0;
+ spin_unlock_irqrestore(&rpm->debug_lock, flags);
+
+ kfree(stacks);
+}
+
+static int cmphandle(const void *_a, const void *_b)
+{
+ const depot_stack_handle_t * const a = _a, * const b = _b;
+
+ if (*a < *b)
+ return -1;
+ else if (*a > *b)
+ return 1;
+ else
+ return 0;
+}
+
+static void show_intel_runtime_pm_wakeref(struct drm_i915_private *i915)
+{
+ struct i915_runtime_pm *rpm = &i915->runtime_pm;
+ unsigned long entries[STACKDEPTH];
+ depot_stack_handle_t *stacks;
+ unsigned long flags, count, i;
+ char *buf;
+
+ spin_lock_irqsave(&rpm->debug_lock, flags);
+ stacks = fetch_and_zero(&rpm->debug_owners);
+ count = fetch_and_zero(&rpm->debug_count);
+ spin_unlock_irqrestore(&rpm->debug_lock, flags);
+ if (!count)
+ return;
+
+ DRM_DEBUG_DRIVER("leaked %lu wakerefs\n", count);
+
+ buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!buf)
+ goto out_stacks;
+
+ sort(stacks, count, sizeof(*stacks), cmphandle, NULL);
+
+ for (i = 0; i < count; i++) {
+ struct stack_trace trace = {
+ .entries = entries,
+ .max_entries = ARRAY_SIZE(entries),
+ };
+ depot_stack_handle_t stack = stacks[i];
+ unsigned long rep;
+
+ rep = 1;
+ while (i + 1 < count && stacks[i + 1] == stack)
+ rep++, i++;
+ depot_fetch_stack(stack, &trace);
+ snprint_stack_trace(buf, PAGE_SIZE, &trace, 0);
+ DRM_DEBUG_DRIVER("wakeref x%lu at\n%s", rep, buf);
+ }
+
+ kfree(buf);
+out_stacks:
+ kfree(stacks);
+}
+
+#else
+
+static void init_intel_runtime_pm_wakeref(struct drm_i915_private *i915)
+{
+}
+
+static void track_intel_runtime_pm_wakeref(struct drm_i915_private *i915)
+{
+}
+
+static void untrack_intel_runtime_pm_wakeref(struct drm_i915_private *i915)
+{
+}
+
+static void show_intel_runtime_pm_wakeref(struct drm_i915_private *i915)
+{
+}
+
+#endif
+
bool intel_display_power_well_is_enabled(struct drm_i915_private *dev_priv,
enum i915_power_well_id power_well_id);
@@ -3919,7 +4056,7 @@ void intel_power_domains_verify_state(struct
drm_i915_private *dev_priv)
/**
* intel_runtime_pm_get - grab a runtime pm reference
- * @dev_priv: i915 device instance
+ * @i915: i915 device instance
*
* This function grabs a device-level runtime pm reference (mostly used for GEM
* code to ensure the GTT or GT is on) and ensures that it is powered up.
@@ -3927,22 +4064,24 @@ void intel_power_domains_verify_state(struct
drm_i915_private *dev_priv)
* Any runtime pm reference obtained by this function must have a symmetric
* call to intel_runtime_pm_put() to release the reference again.
*/
-void intel_runtime_pm_get(struct drm_i915_private *dev_priv)
+void intel_runtime_pm_get(struct drm_i915_private *i915)
{
- struct pci_dev *pdev = dev_priv->drm.pdev;
+ struct pci_dev *pdev = i915->drm.pdev;
struct device *kdev = &pdev->dev;
int ret;
ret = pm_runtime_get_sync(kdev);
WARN_ONCE(ret < 0, "pm_runtime_get_sync() failed: %d\n", ret);
- atomic_inc(&dev_priv->runtime_pm.wakeref_count);
- assert_rpm_wakelock_held(dev_priv);
+ atomic_inc(&i915->runtime_pm.wakeref_count);
+ assert_rpm_wakelock_held(i915);
+
+ track_intel_runtime_pm_wakeref(i915);
}
/**
* intel_runtime_pm_get_if_in_use - grab a runtime pm reference if device in
use
- * @dev_priv: i915 device instance
+ * @i915: 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. It is illegal to try
@@ -3953,10 +4092,10 @@ void intel_runtime_pm_get(struct drm_i915_private
*dev_priv)
*
* Returns: True if the wakeref was acquired, or False otherwise.
*/
-bool intel_runtime_pm_get_if_in_use(struct drm_i915_private *dev_priv)
+bool intel_runtime_pm_get_if_in_use(struct drm_i915_private *i915)
{
if (IS_ENABLED(CONFIG_PM)) {
- struct pci_dev *pdev = dev_priv->drm.pdev;
+ struct pci_dev *pdev = i915->drm.pdev;
struct device *kdev = &pdev->dev;
/*
@@ -3969,15 +4108,17 @@ bool intel_runtime_pm_get_if_in_use(struct
drm_i915_private *dev_priv)
return false;
}
- atomic_inc(&dev_priv->runtime_pm.wakeref_count);
- assert_rpm_wakelock_held(dev_priv);
+ atomic_inc(&i915->runtime_pm.wakeref_count);
+ assert_rpm_wakelock_held(i915);
+
+ track_intel_runtime_pm_wakeref(i915);
return true;
}
/**
* intel_runtime_pm_get_noresume - grab a runtime pm reference
- * @dev_priv: i915 device instance
+ * @i915: i915 device instance
*
* This function grabs a device-level runtime pm reference (mostly used for GEM
* code to ensure the GTT or GT is on).
@@ -3992,32 +4133,35 @@ bool intel_runtime_pm_get_if_in_use(struct
drm_i915_private *dev_priv)
* Any runtime pm reference obtained by this function must have a symmetric
* call to intel_runtime_pm_put() to release the reference again.
*/
-void intel_runtime_pm_get_noresume(struct drm_i915_private *dev_priv)
+void intel_runtime_pm_get_noresume(struct drm_i915_private *i915)
{
- struct pci_dev *pdev = dev_priv->drm.pdev;
+ struct pci_dev *pdev = i915->drm.pdev;
struct device *kdev = &pdev->dev;
- assert_rpm_wakelock_held(dev_priv);
+ assert_rpm_wakelock_held(i915);
pm_runtime_get_noresume(kdev);
- atomic_inc(&dev_priv->runtime_pm.wakeref_count);
+ atomic_inc(&i915->runtime_pm.wakeref_count);
+
+ track_intel_runtime_pm_wakeref(i915);
}
/**
* intel_runtime_pm_put - release a runtime pm reference
- * @dev_priv: i915 device instance
+ * @i915: i915 device instance
*
* This function drops the device-level runtime pm reference obtained by
* intel_runtime_pm_get() and might power down the corresponding
* hardware block right away if this is the last reference.
*/
-void intel_runtime_pm_put(struct drm_i915_private *dev_priv)
+void intel_runtime_pm_put(struct drm_i915_private *i915)
{
- struct pci_dev *pdev = dev_priv->drm.pdev;
+ struct pci_dev *pdev = i915->drm.pdev;
struct device *kdev = &pdev->dev;
- assert_rpm_wakelock_held(dev_priv);
- atomic_dec(&dev_priv->runtime_pm.wakeref_count);
+ assert_rpm_wakelock_held(i915);
+ if (atomic_dec_and_test(&i915->runtime_pm.wakeref_count))
+ untrack_intel_runtime_pm_wakeref(i915);
pm_runtime_mark_last_busy(kdev);
pm_runtime_put_autosuspend(kdev);
@@ -4025,7 +4169,7 @@ void intel_runtime_pm_put(struct drm_i915_private
*dev_priv)
/**
* intel_runtime_pm_enable - enable runtime pm
- * @dev_priv: i915 device instance
+ * @i915: i915 device instance
*
* This function enables runtime pm at the end of the driver load sequence.
*
@@ -4033,9 +4177,9 @@ void intel_runtime_pm_put(struct drm_i915_private
*dev_priv)
* subordinate display power domains. That is only done on the first modeset
* using intel_display_set_init_power().
*/
-void intel_runtime_pm_enable(struct drm_i915_private *dev_priv)
+void intel_runtime_pm_enable(struct drm_i915_private *i915)
{
- struct pci_dev *pdev = dev_priv->drm.pdev;
+ struct pci_dev *pdev = i915->drm.pdev;
struct device *kdev = &pdev->dev;
/*
@@ -4057,7 +4201,7 @@ void intel_runtime_pm_enable(struct drm_i915_private
*dev_priv)
* so the driver's own RPM reference tracking asserts also work on
* platforms without RPM support.
*/
- if (!HAS_RUNTIME_PM(dev_priv)) {
+ if (!HAS_RUNTIME_PM(i915)) {
int ret;
pm_runtime_dont_use_autosuspend(kdev);
@@ -4075,17 +4219,36 @@ 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)
+void intel_runtime_pm_disable(struct drm_i915_private *i915)
{
- struct pci_dev *pdev = dev_priv->drm.pdev;
+ struct pci_dev *pdev = i915->drm.pdev;
struct device *kdev = &pdev->dev;
/* Transfer rpm ownership back to core */
- WARN(pm_runtime_get_sync(&dev_priv->drm.pdev->dev) < 0,
+ WARN(pm_runtime_get_sync(kdev) < 0,
"Failed to pass rpm ownership back to core\n");
pm_runtime_dont_use_autosuspend(kdev);
- if (!HAS_RUNTIME_PM(dev_priv))
+ if (!HAS_RUNTIME_PM(i915))
pm_runtime_put(kdev);
}
+
+void intel_runtime_pm_cleanup(struct drm_i915_private *i915)
+{
+ struct i915_runtime_pm *rpm = &i915->runtime_pm;
+
+ if (WARN(atomic_read(&rpm->wakeref_count),
+ "i915->runtime_pm.wakeref_count=%d on cleanup\n",
+ atomic_read(&rpm->wakeref_count))) {
+ show_intel_runtime_pm_wakeref(i915);
+ atomic_set(&rpm->wakeref_count, 0);
+ }
+
+ untrack_intel_runtime_pm_wakeref(i915);
+}
+
+void intel_runtime_pm_init_early(struct drm_i915_private *i915)
+{
+ init_intel_runtime_pm_wakeref(i915);
+}
diff --git a/drivers/gpu/drm/i915/selftests/mock_gem_device.c
b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
index 43ed8b28aeaa..0eb283e7fc96 100644
--- a/drivers/gpu/drm/i915/selftests/mock_gem_device.c
+++ b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
@@ -154,15 +154,17 @@ struct drm_i915_private *mock_gem_device(void)
pdev->dev.archdata.iommu = (void *)-1;
#endif
+ i915 = (struct drm_i915_private *)(pdev + 1);
+ pci_set_drvdata(pdev, i915);
+
+ intel_runtime_pm_init_early(i915);
+
dev_pm_domain_set(&pdev->dev, &pm_domain);
pm_runtime_enable(&pdev->dev);
pm_runtime_dont_use_autosuspend(&pdev->dev);
if (pm_runtime_enabled(&pdev->dev))
WARN_ON(pm_runtime_get_sync(&pdev->dev));
- i915 = (struct drm_i915_private *)(pdev + 1);
- pci_set_drvdata(pdev, i915);
-
err = drm_dev_init(&i915->drm, &mock_driver, &pdev->dev);
if (err) {
pr_err("Failed to initialise mock GEM device: err=%d\n", err);
--
2.18.0
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