Commit 4547c255 authored by Imre Deak's avatar Imre Deak
Browse files

drm/i915: Add support for tracking wakerefs w/o power-on guarantee 



It's useful to track runtime PM refs that don't guarantee a device
power-on state to the rest of the driver. One such case is holding a
reference that will be put asynchronously, during which normal users
without their own reference shouldn't access the HW. A follow-up patch
will add support for disabling display power domains asynchronously
which needs this.

For this we can split wakeref_count into a low half-word tracking
all references (raw-wakerefs) and a high half-word tracking
references guaranteeing a power-on state (wakelocks).

Follow-up patches will make use of the API added here.

While at it add the missing docbook header for the unchecked
display-power and runtime_pm put functions.

No functional changes, except for printing leaked raw-wakerefs
and wakelocks separately in intel_runtime_pm_cleanup().

v2:
- Track raw wakerefs/wakelocks in the low/high half-word of
  wakeref_count, instead of adding a new counter. (Chris)
v3:
- Add a struct_member(T, m) helper instead of open-coding it. (Chris)
- Checkpatch indentation formatting fix.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarImre Deak <imre.deak@intel.com>
Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190509173446.31095-2-imre.deak@intel.com
parent 1aa37508

drivers/gpu/drm/i915/i915_utils.h

+3 −1
Original line number Diff line number Diff line
@@ -102,6 +102,8 @@ 
#define page_pack_bits(ptr, bits) ptr_pack_bits(ptr, bits, PAGE_SHIFT)

#define page_unpack_bits(ptr, bits) ptr_unpack_bits(ptr, bits, PAGE_SHIFT)



#define struct_member(T, member) (((T *)0)->member)



#define ptr_offset(ptr, member) offsetof(typeof(*(ptr)), member)



#define fetch_and_zero(ptr) ({						\
@@ -118,7 +120,7 @@ 
 */

#define container_of_user(ptr, type, member) ({				\

	void __user *__mptr = (void __user *)(ptr);			\

	BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) &&	\

	BUILD_BUG_ON_MSG(!__same_type(*(ptr), struct_member(type, member)) && \

			 !__same_type(*(ptr), void),			\

			 "pointer type mismatch in container_of()");	\

	((type __user *)(__mptr - offsetof(type, member))); })

drivers/gpu/drm/i915/intel_drv.h

+47 −5
Original line number Diff line number Diff line
@@ -1620,6 +1620,24 @@ unsigned int i9xx_plane_max_stride(struct intel_plane *plane, 
int bdw_get_pipemisc_bpp(struct intel_crtc *crtc);



/* intel_runtime_pm.c */

#define BITS_PER_WAKEREF	\

	BITS_PER_TYPE(struct_member(struct i915_runtime_pm, wakeref_count))

#define INTEL_RPM_WAKELOCK_SHIFT	(BITS_PER_WAKEREF / 2)

#define INTEL_RPM_WAKELOCK_BIAS		(1 << INTEL_RPM_WAKELOCK_SHIFT)

#define INTEL_RPM_RAW_WAKEREF_MASK	(INTEL_RPM_WAKELOCK_BIAS - 1)



static inline int

intel_rpm_raw_wakeref_count(int wakeref_count)

{

	return wakeref_count & INTEL_RPM_RAW_WAKEREF_MASK;

}



static inline int

intel_rpm_wakelock_count(int wakeref_count)

{

	return wakeref_count >> INTEL_RPM_WAKELOCK_SHIFT;

}



static inline void

assert_rpm_device_not_suspended(struct i915_runtime_pm *rpm)

{
@@ -1628,11 +1646,33 @@ assert_rpm_device_not_suspended(struct i915_runtime_pm *rpm) 
}



static inline void

__assert_rpm_wakelock_held(struct i915_runtime_pm *rpm)

____assert_rpm_raw_wakeref_held(struct i915_runtime_pm *rpm, int wakeref_count)

{

	assert_rpm_device_not_suspended(rpm);

	WARN_ONCE(!atomic_read(&rpm->wakeref_count),

		  "RPM wakelock ref not held during HW access");

	WARN_ONCE(!intel_rpm_raw_wakeref_count(wakeref_count),

		  "RPM raw-wakeref not held\n");

}



static inline void

____assert_rpm_wakelock_held(struct i915_runtime_pm *rpm, int wakeref_count)

{

	____assert_rpm_raw_wakeref_held(rpm, wakeref_count);

	WARN_ONCE(!intel_rpm_wakelock_count(wakeref_count),

		  "RPM wakelock ref not held during HW access\n");

}



static inline void

assert_rpm_raw_wakeref_held(struct drm_i915_private *i915)

{

	struct i915_runtime_pm *rpm = &i915->runtime_pm;



	____assert_rpm_raw_wakeref_held(rpm, atomic_read(&rpm->wakeref_count));

}



static inline void

__assert_rpm_wakelock_held(struct i915_runtime_pm *rpm)

{

	____assert_rpm_wakelock_held(rpm, atomic_read(&rpm->wakeref_count));

}



static inline void
@@ -1662,7 +1702,8 @@ assert_rpm_wakelock_held(struct drm_i915_private *i915) 
static inline void

disable_rpm_wakeref_asserts(struct drm_i915_private *i915)

{

	atomic_inc(&i915->runtime_pm.wakeref_count);

	atomic_add(INTEL_RPM_WAKELOCK_BIAS + 1,

		   &i915->runtime_pm.wakeref_count);

}



/**
@@ -1679,7 +1720,8 @@ disable_rpm_wakeref_asserts(struct drm_i915_private *i915) 
static inline void

enable_rpm_wakeref_asserts(struct drm_i915_private *i915)

{

	atomic_dec(&i915->runtime_pm.wakeref_count);

	atomic_sub(INTEL_RPM_WAKELOCK_BIAS + 1,

		   &i915->runtime_pm.wakeref_count);

}



#endif /* __INTEL_DRV_H__ */

drivers/gpu/drm/i915/intel_runtime_pm.c

+109 −33
Original line number Diff line number Diff line
@@ -110,9 +110,6 @@ track_intel_runtime_pm_wakeref(struct drm_i915_private *i915) 
	depot_stack_handle_t stack, *stacks;

	unsigned long flags;



	atomic_inc(&rpm->wakeref_count);

	assert_rpm_wakelock_held(i915);



	if (!HAS_RUNTIME_PM(i915))

		return -1;
@@ -140,7 +137,7 @@ track_intel_runtime_pm_wakeref(struct drm_i915_private *i915) 
	return stack;

}



static void cancel_intel_runtime_pm_wakeref(struct drm_i915_private *i915,

static void untrack_intel_runtime_pm_wakeref(struct drm_i915_private *i915,

					     depot_stack_handle_t stack)

{

	struct i915_runtime_pm *rpm = &i915->runtime_pm;
@@ -236,14 +233,13 @@ __print_intel_runtime_pm_wakeref(struct drm_printer *p, 
}



static noinline void

untrack_intel_runtime_pm_wakeref(struct drm_i915_private *i915)

__intel_wakeref_dec_and_check_tracking(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,

					&rpm->debug.lock,

					flags)) {
@@ -311,19 +307,51 @@ static void init_intel_runtime_pm_wakeref(struct drm_i915_private *i915) 
static 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 -1;

}



static void untrack_intel_runtime_pm_wakeref(struct drm_i915_private *i915)

static void untrack_intel_runtime_pm_wakeref(struct drm_i915_private *i915,

					     intel_wakeref_t wref)

{

}



static void

__intel_wakeref_dec_and_check_tracking(struct drm_i915_private *i915)

{

	assert_rpm_wakelock_held(i915);

	atomic_dec(&i915->runtime_pm.wakeref_count);

}



#endif



static void

intel_runtime_pm_acquire(struct drm_i915_private *i915, bool wakelock)

{

	struct i915_runtime_pm *rpm = &i915->runtime_pm;



	if (wakelock) {

		atomic_add(1 + INTEL_RPM_WAKELOCK_BIAS, &rpm->wakeref_count);

		assert_rpm_wakelock_held(i915);

	} else {

		atomic_inc(&rpm->wakeref_count);

		assert_rpm_raw_wakeref_held(i915);

	}

}



static void

intel_runtime_pm_release(struct drm_i915_private *i915, int wakelock)

{

	struct i915_runtime_pm *rpm = &i915->runtime_pm;



	if (wakelock) {

		assert_rpm_wakelock_held(i915);

		atomic_sub(INTEL_RPM_WAKELOCK_BIAS, &rpm->wakeref_count);

	} else {

		assert_rpm_raw_wakeref_held(i915);

	}



	__intel_wakeref_dec_and_check_tracking(i915);

}



bool intel_display_power_well_is_enabled(struct drm_i915_private *dev_priv,

					 enum i915_power_well_id power_well_id);
@@ -1946,13 +1974,17 @@ static void __intel_display_power_put(struct drm_i915_private *dev_priv, 
}



/**

 * intel_display_power_put - release a power domain reference

 * intel_display_power_put_unchecked - release an unchecked power domain reference

 * @dev_priv: i915 device instance

 * @domain: power domain to reference

 *

 * This function drops the power domain reference obtained by

 * intel_display_power_get() and might power down the corresponding hardware

 * block right away if this is the last reference.

 *

 * This function exists only for historical reasons and should be avoided in

 * new code, as the correctness of its use cannot be checked. Always use

 * intel_display_power_put() instead.

 */

void intel_display_power_put_unchecked(struct drm_i915_private *dev_priv,

				       enum intel_display_power_domain domain)
@@ -1962,6 +1994,16 @@ void intel_display_power_put_unchecked(struct drm_i915_private *dev_priv, 
}



#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)

/**

 * intel_display_power_put - release a power domain reference

 * @dev_priv: i915 device instance

 * @domain: power domain to reference

 * @wakeref: wakeref acquired for the reference that is being released

 *

 * This function drops the power domain reference obtained by

 * intel_display_power_get() and might power down the corresponding hardware

 * block right away if this is the last reference.

 */

void intel_display_power_put(struct drm_i915_private *dev_priv,

			     enum intel_display_power_domain domain,

			     intel_wakeref_t wakeref)
@@ -4579,6 +4621,21 @@ static void intel_power_domains_verify_state(struct drm_i915_private *i915) 


#endif



static intel_wakeref_t __intel_runtime_pm_get(struct drm_i915_private *i915,

					      bool wakelock)

{

	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);



	intel_runtime_pm_acquire(i915, wakelock);



	return track_intel_runtime_pm_wakeref(i915);

}



/**

 * intel_runtime_pm_get - grab a runtime pm reference

 * @i915: i915 device instance
@@ -4593,14 +4650,7 @@ static void intel_power_domains_verify_state(struct drm_i915_private *i915) 
 */

intel_wakeref_t intel_runtime_pm_get(struct drm_i915_private *i915)

{

	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);



	return track_intel_runtime_pm_wakeref(i915);

	return __intel_runtime_pm_get(i915, true);

}



/**
@@ -4633,6 +4683,8 @@ intel_wakeref_t intel_runtime_pm_get_if_in_use(struct drm_i915_private *i915) 
			return 0;

	}



	intel_runtime_pm_acquire(i915, true);



	return track_intel_runtime_pm_wakeref(i915);

}
@@ -4663,33 +4715,56 @@ intel_wakeref_t intel_runtime_pm_get_noresume(struct drm_i915_private *i915) 
	assert_rpm_wakelock_held(i915);

	pm_runtime_get_noresume(kdev);



	intel_runtime_pm_acquire(i915, true);



	return track_intel_runtime_pm_wakeref(i915);

}



static void __intel_runtime_pm_put(struct drm_i915_private *i915,

				   intel_wakeref_t wref,

				   bool wakelock)

{

	struct pci_dev *pdev = i915->drm.pdev;

	struct device *kdev = &pdev->dev;



	untrack_intel_runtime_pm_wakeref(i915, wref);



	intel_runtime_pm_release(i915, wakelock);



	pm_runtime_mark_last_busy(kdev);

	pm_runtime_put_autosuspend(kdev);

}



/**

 * intel_runtime_pm_put - release a runtime pm reference

 * intel_runtime_pm_put_unchecked - release an unchecked runtime pm reference

 * @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.

 *

 * This function exists only for historical reasons and should be avoided in

 * new code, as the correctness of its use cannot be checked. Always use

 * intel_runtime_pm_put() instead.

 */

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(i915, -1, true);

}



#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)

/**

 * intel_runtime_pm_put - release a runtime pm reference

 * @i915: i915 device instance

 * @wref: wakeref acquired for the reference that is being released

 *

 * 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 *i915, intel_wakeref_t wref)

{

	cancel_intel_runtime_pm_wakeref(i915, wref);

	intel_runtime_pm_put_unchecked(i915);

	__intel_runtime_pm_put(i915, wref, true);

}

#endif
@@ -4767,10 +4842,11 @@ void intel_runtime_pm_cleanup(struct drm_i915_private *i915) 


	count = atomic_fetch_inc(&rpm->wakeref_count); /* balance untrack */

	WARN(count,

	     "i915->runtime_pm.wakeref_count=%d on cleanup\n",

	     count);

	     "i915 raw-wakerefs=%d wakelocks=%d on cleanup\n",

	     intel_rpm_raw_wakeref_count(count),

	     intel_rpm_wakelock_count(count));



	untrack_intel_runtime_pm_wakeref(i915);

	intel_runtime_pm_release(i915, false);

}



void intel_runtime_pm_init_early(struct drm_i915_private *i915)

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