Commit bd780f37 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Track all held rpm wakerefs 



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.

v2: Use skip=0 for unwinding the stack as it appears our noinline
function doesn't appear on the stack (nor does save_stack_trace itself!)
v3: Allow rpm->debug_count to disappear between inspections and so
avoid calling krealloc(0) as that may return a ZERO_PTR not NULL! (Mika)
v4: Show who last acquire/released the runtime pm

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Tested-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190114142129.24398-1-chris@chris-wilson.co.uk
parent 74256b7e

drivers/gpu/drm/i915/Kconfig.debug

+2 −1
Original line number Diff line number Diff line
@@ -21,11 +21,11 @@ config DRM_I915_DEBUG 
        select DEBUG_FS

        select PREEMPT_COUNT

        select I2C_CHARDEV

        select STACKDEPOT

        select DRM_DP_AUX_CHARDEV

        select X86_MSR # used by igt/pm_rpm

        select DRM_VGEM # used by igt/prime_vgem (dmabuf interop checks)

        select DRM_DEBUG_MM if DRM=y

        select STACKDEPOT if DRM=y # for DRM_DEBUG_MM

	select DRM_DEBUG_SELFTEST

	select SW_SYNC # signaling validation framework (igt/syncobj*)

	select DRM_I915_SW_FENCE_DEBUG_OBJECTS
@@ -173,6 +173,7 @@ config DRM_I915_DEBUG_RUNTIME_PM 
	bool "Enable extra state checking for runtime PM"

	depends on DRM_I915

	default n

	select STACKDEPOT

	help

	  Choose this option to turn on extra state checking for the

	  runtime PM functionality. This may introduce overhead during

drivers/gpu/drm/i915/i915_debugfs.c

+6 −0
Original line number Diff line number Diff line
@@ -2702,6 +2702,12 @@ static int i915_runtime_pm_status(struct seq_file *m, void *unused) 
		   pci_power_name(pdev->current_state),

		   pdev->current_state);



	if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)) {

		struct drm_printer p = drm_seq_file_printer(m);



		print_intel_runtime_pm_wakeref(dev_priv, &p);

	}



	return 0;

}

drivers/gpu/drm/i915/i915_drv.c

+5 −3
Original line number Diff line number Diff line
@@ -905,6 +905,7 @@ static int i915_driver_init_early(struct drm_i915_private *dev_priv) 
	mutex_init(&dev_priv->pps_mutex);



	i915_memcpy_init_early(dev_priv);

	intel_runtime_pm_init_early(dev_priv);



	ret = i915_workqueues_init(dev_priv);

	if (ret < 0)
@@ -1807,8 +1808,7 @@ void i915_driver_unload(struct drm_device *dev) 
	i915_driver_cleanup_mmio(dev_priv);



	enable_rpm_wakeref_asserts(dev_priv);



	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)
@@ -2010,6 +2010,8 @@ 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;

}
@@ -2965,7 +2967,7 @@ 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");

drivers/gpu/drm/i915/i915_drv.h

+20 −0
Original line number Diff line number Diff line
@@ -45,6 +45,7 @@ 
#include <linux/pm_qos.h>

#include <linux/reservation.h>

#include <linux/shmem_fs.h>

#include <linux/stackdepot.h>



#include <drm/intel-gtt.h>

#include <drm/drm_legacy.h> /* for struct drm_dma_handle */
@@ -1156,6 +1157,25 @@ struct i915_runtime_pm { 
	atomic_t wakeref_count;

	bool suspended;

	bool irqs_enabled;



#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)

	/*

	 * To aide detection of wakeref leaks and general misuse, we

	 * track all wakeref holders. With manual markup (i.e. returning

	 * a cookie to each rpm_get caller which they then supply to their

	 * paired rpm_put) we can remove corresponding pairs of and keep

	 * the array trimmed to active wakerefs.

	 */

	struct intel_runtime_pm_debug {

		spinlock_t lock;



		depot_stack_handle_t last_acquire;

		depot_stack_handle_t last_release;



		depot_stack_handle_t *owners;

		unsigned long count;

	} debug;

#endif

};



enum intel_pipe_crc_source {

drivers/gpu/drm/i915/intel_drv.h

+29 −15
Original line number Diff line number Diff line
@@ -41,6 +41,8 @@ 
#include <drm/drm_atomic.h>

#include <media/cec-notifier.h>



struct drm_printer;



/**

 * __wait_for - magic wait macro

 *
@@ -2084,6 +2086,7 @@ bool intel_psr_enabled(struct intel_dp *intel_dp); 
void intel_init_quirks(struct drm_i915_private *dev_priv);



/* 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);
@@ -2106,6 +2109,7 @@ 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);
@@ -2123,23 +2127,23 @@ 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.
@@ -2156,14 +2160,14 @@ 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
@@ -2173,15 +2177,25 @@ 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);



#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)

void print_intel_runtime_pm_wakeref(struct drm_i915_private *i915,

				    struct drm_printer *p);

#else

static inline void print_intel_runtime_pm_wakeref(struct drm_i915_private *i915,

						  struct drm_printer *p)

{

}

#endif



void chv_phy_powergate_lanes(struct intel_encoder *encoder,

			     bool override, unsigned int mask);

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