aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/gpu/drm/i915/intel_runtime_pm.c
blob: 8d1aebc3e8574652153553f82370f7a210d14c84 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
/*
 * Copyright © 2012-2014 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 * Authors:
 *    Eugeni Dodonov <eugeni.dodonov@intel.com>
 *    Daniel Vetter <daniel.vetter@ffwll.ch>
 *
 */

#include <linux/pm_runtime.h>
#include <linux/vgaarb.h>

#include <drm/drm_print.h>

#include "i915_drv.h"

/**
 * DOC: runtime pm
 *
 * The i915 driver supports dynamic enabling and disabling of entire hardware
 * blocks at runtime. This is especially important on the display side where
 * software is supposed to control many power gates manually on recent hardware,
 * since on the GT side a lot of the power management is done by the hardware.
 * But even there some manual control at the device level is required.
 *
 * Since i915 supports a diverse set of platforms with a unified codebase and
 * hardware engineers just love to shuffle functionality around between power
 * domains there's a sizeable amount of indirection required. This file provides
 * generic functions to the driver for grabbing and releasing references for
 * abstract power domains. It then maps those to the actual power wells
 * present for a given platform.
 */

#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)

#include <linux/sort.h>

#define STACKDEPTH 8

static noinline depot_stack_handle_t __save_depot_stack(void)
{
	unsigned long entries[STACKDEPTH];
	unsigned int n;

	n = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
	return stack_depot_save(entries, n, GFP_NOWAIT | __GFP_NOWARN);
}

static void __print_depot_stack(depot_stack_handle_t stack,
				char *buf, int sz, int indent)
{
	unsigned long *entries;
	unsigned int nr_entries;

	nr_entries = stack_depot_fetch(stack, &entries);
	stack_trace_snprint(buf, sz, entries, nr_entries, indent);
}

static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
{
	spin_lock_init(&rpm->debug.lock);
}

static noinline depot_stack_handle_t
track_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
{
	depot_stack_handle_t stack, *stacks;
	unsigned long flags;

	if (!rpm->available)
		return -1;

	stack = __save_depot_stack();
	if (!stack)
		return -1;

	spin_lock_irqsave(&rpm->debug.lock, flags);

	if (!rpm->debug.count)
		rpm->debug.last_acquire = stack;

	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;
	} else {
		stack = -1;
	}

	spin_unlock_irqrestore(&rpm->debug.lock, flags);

	return stack;
}

static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
					     depot_stack_handle_t stack)
{
	unsigned long flags, n;
	bool found = false;

	if (unlikely(stack == -1))
		return;

	spin_lock_irqsave(&rpm->debug.lock, flags);
	for (n = rpm->debug.count; n--; ) {
		if (rpm->debug.owners[n] == stack) {
			memmove(rpm->debug.owners + n,
				rpm->debug.owners + n + 1,
				(--rpm->debug.count - n) * sizeof(stack));
			found = true;
			break;
		}
	}
	spin_unlock_irqrestore(&rpm->debug.lock, flags);

	if (WARN(!found,
		 "Unmatched wakeref (tracking %lu), count %u\n",
		 rpm->debug.count, atomic_read(&rpm->wakeref_count))) {
		char *buf;

		buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN);
		if (!buf)
			return;

		__print_depot_stack(stack, buf, PAGE_SIZE, 2);
		DRM_DEBUG_DRIVER("wakeref %x from\n%s", stack, buf);

		stack = READ_ONCE(rpm->debug.last_release);
		if (stack) {
			__print_depot_stack(stack, buf, PAGE_SIZE, 2);
			DRM_DEBUG_DRIVER("wakeref last released at\n%s", buf);
		}

		kfree(buf);
	}
}

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
__print_intel_runtime_pm_wakeref(struct drm_printer *p,
				 const struct intel_runtime_pm_debug *dbg)
{
	unsigned long i;
	char *buf;

	buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN);
	if (!buf)
		return;

	if (dbg->last_acquire) {
		__print_depot_stack(dbg->last_acquire, buf, PAGE_SIZE, 2);
		drm_printf(p, "Wakeref last acquired:\n%s", buf);
	}

	if (dbg->last_release) {
		__print_depot_stack(dbg->last_release, buf, PAGE_SIZE, 2);
		drm_printf(p, "Wakeref last released:\n%s", buf);
	}

	drm_printf(p, "Wakeref count: %lu\n", dbg->count);

	sort(dbg->owners, dbg->count, sizeof(*dbg->owners), cmphandle, NULL);

	for (i = 0; i < dbg->count; i++) {
		depot_stack_handle_t stack = dbg->owners[i];
		unsigned long rep;

		rep = 1;
		while (i + 1 < dbg->count && dbg->owners[i + 1] == stack)
			rep++, i++;
		__print_depot_stack(stack, buf, PAGE_SIZE, 2);
		drm_printf(p, "Wakeref x%lu taken at:\n%s", rep, buf);
	}

	kfree(buf);
}

static noinline void
__untrack_all_wakerefs(struct intel_runtime_pm_debug *debug,
		       struct intel_runtime_pm_debug *saved)
{
	*saved = *debug;

	debug->owners = NULL;
	debug->count = 0;
	debug->last_release = __save_depot_stack();
}

static void
dump_and_free_wakeref_tracking(struct intel_runtime_pm_debug *debug)
{
	if (debug->count) {
		struct drm_printer p = drm_debug_printer("i915");

		__print_intel_runtime_pm_wakeref(&p, debug);
	}

	kfree(debug->owners);
}

static noinline void
__intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm)
{
	struct intel_runtime_pm_debug dbg = {};
	unsigned long flags;

	if (!atomic_dec_and_lock_irqsave(&rpm->wakeref_count,
					 &rpm->debug.lock,
					 flags))
		return;

	__untrack_all_wakerefs(&rpm->debug, &dbg);
	spin_unlock_irqrestore(&rpm->debug.lock, flags);

	dump_and_free_wakeref_tracking(&dbg);
}

static noinline void
untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm)
{
	struct intel_runtime_pm_debug dbg = {};
	unsigned long flags;

	spin_lock_irqsave(&rpm->debug.lock, flags);
	__untrack_all_wakerefs(&rpm->debug, &dbg);
	spin_unlock_irqrestore(&rpm->debug.lock, flags);

	dump_and_free_wakeref_tracking(&dbg);
}

void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
				    struct drm_printer *p)
{
	struct intel_runtime_pm_debug dbg = {};

	do {
		unsigned long alloc = dbg.count;
		depot_stack_handle_t *s;

		spin_lock_irq(&rpm->debug.lock);
		dbg.count = rpm->debug.count;
		if (dbg.count <= alloc) {
			memcpy(dbg.owners,
			       rpm->debug.owners,
			       dbg.count * sizeof(*s));
		}
		dbg.last_acquire = rpm->debug.last_acquire;
		dbg.last_release = rpm->debug.last_release;
		spin_unlock_irq(&rpm->debug.lock);
		if (dbg.count <= alloc)
			break;

		s = krealloc(dbg.owners,
			     dbg.count * sizeof(*s),
			     GFP_NOWAIT | __GFP_NOWARN);
		if (!s)
			goto out;

		dbg.owners = s;
	} while (1);

	__print_intel_runtime_pm_wakeref(p, &dbg);

out:
	kfree(dbg.owners);
}

#else

static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
{
}

static depot_stack_handle_t
track_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
{
	return -1;
}

static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
					     intel_wakeref_t wref)
{
}

static void
__intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm)
{
	atomic_dec(&rpm->wakeref_count);
}

static void
untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm)
{
}

#endif

static void
intel_runtime_pm_acquire(struct intel_runtime_pm *rpm, bool wakelock)
{
	if (wakelock) {
		atomic_add(1 + INTEL_RPM_WAKELOCK_BIAS, &rpm->wakeref_count);
		assert_rpm_wakelock_held(rpm);
	} else {
		atomic_inc(&rpm->wakeref_count);
		assert_rpm_raw_wakeref_held(rpm);
	}
}

static void
intel_runtime_pm_release(struct intel_runtime_pm *rpm, int wakelock)
{
	if (wakelock) {
		assert_rpm_wakelock_held(rpm);
		atomic_sub(INTEL_RPM_WAKELOCK_BIAS, &rpm->wakeref_count);
	} else {
		assert_rpm_raw_wakeref_held(rpm);
	}

	__intel_wakeref_dec_and_check_tracking(rpm);
}

static intel_wakeref_t __intel_runtime_pm_get(struct intel_runtime_pm *rpm,
					      bool wakelock)
{
	int ret;

	ret = pm_runtime_get_sync(rpm->kdev);
	WARN_ONCE(ret < 0, "pm_runtime_get_sync() failed: %d\n", ret);

	intel_runtime_pm_acquire(rpm, wakelock);

	return track_intel_runtime_pm_wakeref(rpm);
}

/**
 * intel_runtime_pm_get_raw - grab a raw runtime pm reference
 * @rpm: the intel_runtime_pm structure
 *
 * This is the unlocked version of intel_display_power_is_enabled() and should
 * only be used from error capture and recovery code where deadlocks are
 * possible.
 * This function grabs a device-level runtime pm reference (mostly used for
 * asynchronous PM management from display code) and ensures that it is powered
 * up. Raw references are not considered during wakelock assert checks.
 *
 * Any runtime pm reference obtained by this function must have a symmetric
 * call to intel_runtime_pm_put_raw() to release the reference again.
 *
 * Returns: the wakeref cookie to pass to intel_runtime_pm_put_raw(), evaluates
 * as True if the wakeref was acquired, or False otherwise.
 */
intel_wakeref_t intel_runtime_pm_get_raw(struct intel_runtime_pm *rpm)
{
	return __intel_runtime_pm_get(rpm, false);
}

/**
 * intel_runtime_pm_get - grab a runtime pm reference
 * @rpm: the intel_runtime_pm structure
 *
 * 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.
 *
 * Any runtime pm reference obtained by this function must have a symmetric
 * call to intel_runtime_pm_put() to release the reference again.
 *
 * Returns: the wakeref cookie to pass to intel_runtime_pm_put()
 */
intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm)
{
	return __intel_runtime_pm_get(rpm, true);
}

/**
 * intel_runtime_pm_get_if_in_use - grab a runtime pm reference if device in use
 * @rpm: the intel_runtime_pm structure
 *
 * 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
 * and access the HW should intel_runtime_pm_get_if_in_use() report failure.
 *
 * Any runtime pm reference obtained by this function must have a symmetric
 * call to intel_runtime_pm_put() to release the reference again.
 *
 * Returns: the wakeref cookie to pass to intel_runtime_pm_put(), evaluates
 * as True if the wakeref was acquired, or False otherwise.
 */
intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm)
{
	if (IS_ENABLED(CONFIG_PM)) {
		/*
		 * In cases runtime PM is disabled by the RPM core and we get
		 * an -EINVAL return value we are not supposed to call this
		 * function, since the power state is undefined. This applies
		 * atm to the late/early system suspend/resume handlers.
		 */
		if (pm_runtime_get_if_in_use(rpm->kdev) <= 0)
			return 0;
	}

	intel_runtime_pm_acquire(rpm, true);

	return track_intel_runtime_pm_wakeref(rpm);
}

/**
 * intel_runtime_pm_get_noresume - grab a runtime pm reference
 * @rpm: the intel_runtime_pm structure
 *
 * This function grabs a device-level runtime pm reference (mostly used for GEM
 * code to ensure the GTT or GT is on).
 *
 * It will _not_ power up the device but instead only check that it's powered
 * on.  Therefore it is only valid to call this functions from contexts where
 * the device is known to be powered up and where trying to power it up would
 * result in hilarity and deadlocks. That pretty much means only the system
 * suspend/resume code where this is used to grab runtime pm references for
 * delayed setup down in work items.
 *
 * Any runtime pm reference obtained by this function must have a symmetric
 * call to intel_runtime_pm_put() to release the reference again.
 *
 * Returns: the wakeref cookie to pass to intel_runtime_pm_put()
 */
intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm)
{
	assert_rpm_wakelock_held(rpm);
	pm_runtime_get_noresume(rpm->kdev);

	intel_runtime_pm_acquire(rpm, true);

	return track_intel_runtime_pm_wakeref(rpm);
}

static void __intel_runtime_pm_put(struct intel_runtime_pm *rpm,
				   intel_wakeref_t wref,
				   bool wakelock)
{
	struct device *kdev = rpm->kdev;

	untrack_intel_runtime_pm_wakeref(rpm, wref);

	intel_runtime_pm_release(rpm, wakelock);

	pm_runtime_mark_last_busy(kdev);
	pm_runtime_put_autosuspend(kdev);
}

/**
 * intel_runtime_pm_put_raw - release a raw runtime pm reference
 * @rpm: the intel_runtime_pm structure
 * @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_raw() and might power down the corresponding
 * hardware block right away if this is the last reference.
 */
void
intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
{
	__intel_runtime_pm_put(rpm, wref, false);
}

/**
 * intel_runtime_pm_put_unchecked - release an unchecked runtime pm reference
 * @rpm: the intel_runtime_pm structure
 *
 * 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 intel_runtime_pm *rpm)
{
	__intel_runtime_pm_put(rpm, -1, true);
}

#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
/**
 * intel_runtime_pm_put - release a runtime pm reference
 * @rpm: the intel_runtime_pm structure
 * @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 intel_runtime_pm *rpm, intel_wakeref_t wref)
{
	__intel_runtime_pm_put(rpm, wref, true);
}
#endif

/**
 * intel_runtime_pm_enable - enable runtime pm
 * @rpm: the intel_runtime_pm structure
 *
 * This function enables runtime pm at the end of the driver load sequence.
 *
 * Note that this function does currently not enable runtime pm for the
 * subordinate display power domains. That is done by
 * intel_power_domains_enable().
 */
void intel_runtime_pm_enable(struct intel_runtime_pm *rpm)
{
	struct device *kdev = rpm->kdev;

	/*
	 * Disable the system suspend direct complete optimization, which can
	 * leave the device suspended skipping the driver's suspend handlers
	 * if the device was already runtime suspended. This is needed due to
	 * the difference in our runtime and system suspend sequence and
	 * becaue the HDA driver may require us to enable the audio power
	 * domain during system suspend.
	 */
	dev_pm_set_driver_flags(kdev, DPM_FLAG_NEVER_SKIP);

	pm_runtime_set_autosuspend_delay(kdev, 10000); /* 10s */
	pm_runtime_mark_last_busy(kdev);

	/*
	 * Take a permanent reference to disable the RPM functionality and drop
	 * it only when unloading the driver. Use the low level get/put helpers,
	 * so the driver's own RPM reference tracking asserts also work on
	 * platforms without RPM support.
	 */
	if (!rpm->available) {
		int ret;

		pm_runtime_dont_use_autosuspend(kdev);
		ret = pm_runtime_get_sync(kdev);
		WARN(ret < 0, "pm_runtime_get_sync() failed: %d\n", ret);
	} else {
		pm_runtime_use_autosuspend(kdev);
	}

	/*
	 * The core calls the driver load handler with an RPM reference held.
	 * We drop that here and will reacquire it during unloading in
	 * intel_power_domains_fini().
	 */
	pm_runtime_put_autosuspend(kdev);
}

void intel_runtime_pm_disable(struct intel_runtime_pm *rpm)
{
	struct device *kdev = rpm->kdev;

	/* Transfer rpm ownership back to core */
	WARN(pm_runtime_get_sync(kdev) < 0,
	     "Failed to pass rpm ownership back to core\n");

	pm_runtime_dont_use_autosuspend(kdev);

	if (!rpm->available)
		pm_runtime_put(kdev);
}

void intel_runtime_pm_cleanup(struct intel_runtime_pm *rpm)
{
	int count = atomic_read(&rpm->wakeref_count);

	WARN(count,
	     "i915 raw-wakerefs=%d wakelocks=%d on cleanup\n",
	     intel_rpm_raw_wakeref_count(count),
	     intel_rpm_wakelock_count(count));

	untrack_all_intel_runtime_pm_wakerefs(rpm);
}

void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm)
{
	struct drm_i915_private *i915 =
			container_of(rpm, struct drm_i915_private, runtime_pm);
	struct pci_dev *pdev = i915->drm.pdev;
	struct device *kdev = &pdev->dev;

	rpm->kdev = kdev;
	rpm->available = HAS_RUNTIME_PM(i915);

	init_intel_runtime_pm_wakeref(rpm);
}