summaryrefslogtreecommitdiff
path: root/drivers/gpu/drm/qxl/qxl_cmd.c
blob: 08b0823c93d526405d506aca4849f2c83a9d9eb5 (plain)
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
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
/*
 * Copyright 2013 Red Hat Inc.
 *
 * 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 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 COPYRIGHT HOLDER(S) OR AUTHOR(S) 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: Dave Airlie
 *          Alon Levy
 */

/* QXL cmd/ring handling */

#include "qxl_drv.h"
#include "qxl_object.h"

static int qxl_reap_surface_id(struct qxl_device *qdev, int max_to_reap);

struct ring {
	struct qxl_ring_header      header;
	uint8_t                     elements[0];
};

struct qxl_ring {
	struct ring	       *ring;
	int			element_size;
	int			n_elements;
	int			prod_notify;
	wait_queue_head_t      *push_event;
	spinlock_t             lock;
};

void qxl_ring_free(struct qxl_ring *ring)
{
	kfree(ring);
}

struct qxl_ring *
qxl_ring_create(struct qxl_ring_header *header,
		int element_size,
		int n_elements,
		int prod_notify,
		bool set_prod_notify,
		wait_queue_head_t *push_event)
{
	struct qxl_ring *ring;

	ring = kmalloc(sizeof(*ring), GFP_KERNEL);
	if (!ring)
		return NULL;

	ring->ring = (struct ring *)header;
	ring->element_size = element_size;
	ring->n_elements = n_elements;
	ring->prod_notify = prod_notify;
	ring->push_event = push_event;
	if (set_prod_notify)
		header->notify_on_prod = ring->n_elements;
	spin_lock_init(&ring->lock);
	return ring;
}

static int qxl_check_header(struct qxl_ring *ring)
{
	int ret;
	struct qxl_ring_header *header = &(ring->ring->header);
	unsigned long flags;
	spin_lock_irqsave(&ring->lock, flags);
	ret = header->prod - header->cons < header->num_items;
	if (ret == 0)
		header->notify_on_cons = header->cons + 1;
	spin_unlock_irqrestore(&ring->lock, flags);
	return ret;
}

static int qxl_check_idle(struct qxl_ring *ring)
{
	int ret;
	struct qxl_ring_header *header = &(ring->ring->header);
	unsigned long flags;
	spin_lock_irqsave(&ring->lock, flags);
	ret = header->prod == header->cons;
	spin_unlock_irqrestore(&ring->lock, flags);
	return ret;
}

int qxl_ring_push(struct qxl_ring *ring,
		  const void *new_elt, bool interruptible)
{
	struct qxl_ring_header *header = &(ring->ring->header);
	uint8_t *elt;
	int idx, ret;
	unsigned long flags;
	spin_lock_irqsave(&ring->lock, flags);
	if (header->prod - header->cons == header->num_items) {
		header->notify_on_cons = header->cons + 1;
		mb();
		spin_unlock_irqrestore(&ring->lock, flags);
		if (!drm_can_sleep()) {
			while (!qxl_check_header(ring))
				udelay(1);
		} else {
			if (interruptible) {
				ret = wait_event_interruptible(*ring->push_event,
							       qxl_check_header(ring));
				if (ret)
					return ret;
			} else {
				wait_event(*ring->push_event,
					   qxl_check_header(ring));
			}

		}
		spin_lock_irqsave(&ring->lock, flags);
	}

	idx = header->prod & (ring->n_elements - 1);
	elt = ring->ring->elements + idx * ring->element_size;

	memcpy((void *)elt, new_elt, ring->element_size);

	header->prod++;

	mb();

	if (header->prod == header->notify_on_prod)
		outb(0, ring->prod_notify);

	spin_unlock_irqrestore(&ring->lock, flags);
	return 0;
}

static bool qxl_ring_pop(struct qxl_ring *ring,
			 void *element)
{
	volatile struct qxl_ring_header *header = &(ring->ring->header);
	volatile uint8_t *ring_elt;
	int idx;
	unsigned long flags;
	spin_lock_irqsave(&ring->lock, flags);
	if (header->cons == header->prod) {
		header->notify_on_prod = header->cons + 1;
		spin_unlock_irqrestore(&ring->lock, flags);
		return false;
	}

	idx = header->cons & (ring->n_elements - 1);
	ring_elt = ring->ring->elements + idx * ring->element_size;

	memcpy(element, (void *)ring_elt, ring->element_size);

	header->cons++;

	spin_unlock_irqrestore(&ring->lock, flags);
	return true;
}

int
qxl_push_command_ring_release(struct qxl_device *qdev, struct qxl_release *release,
			      uint32_t type, bool interruptible)
{
	struct qxl_command cmd;

	cmd.type = type;
	cmd.data = qxl_bo_physical_address(qdev, release->bos[0], release->release_offset);

	return qxl_ring_push(qdev->command_ring, &cmd, interruptible);
}

int
qxl_push_cursor_ring_release(struct qxl_device *qdev, struct qxl_release *release,
			     uint32_t type, bool interruptible)
{
	struct qxl_command cmd;

	cmd.type = type;
	cmd.data = qxl_bo_physical_address(qdev, release->bos[0], release->release_offset);

	return qxl_ring_push(qdev->cursor_ring, &cmd, interruptible);
}

bool qxl_queue_garbage_collect(struct qxl_device *qdev, bool flush)
{
	if (!qxl_check_idle(qdev->release_ring)) {
		queue_work(qdev->gc_queue, &qdev->gc_work);
		if (flush)
			flush_work(&qdev->gc_work);
		return true;
	}
	return false;
}

int qxl_garbage_collect(struct qxl_device *qdev)
{
	struct qxl_release *release;
	uint64_t id, next_id;
	int i = 0;
	int ret;
	union qxl_release_info *info;

	while (qxl_ring_pop(qdev->release_ring, &id)) {
		QXL_INFO(qdev, "popped %lld\n", id);
		while (id) {
			release = qxl_release_from_id_locked(qdev, id);
			if (release == NULL)
				break;

			ret = qxl_release_reserve(qdev, release, false);
			if (ret) {
				qxl_io_log(qdev, "failed to reserve release on garbage collect %lld\n", id);
				DRM_ERROR("failed to reserve release %lld\n", id);
			}

			info = qxl_release_map(qdev, release);
			next_id = info->next;
			qxl_release_unmap(qdev, release, info);

			qxl_release_unreserve(qdev, release);
			QXL_INFO(qdev, "popped %lld, next %lld\n", id,
				next_id);

			switch (release->type) {
			case QXL_RELEASE_DRAWABLE:
			case QXL_RELEASE_SURFACE_CMD:
			case QXL_RELEASE_CURSOR_CMD:
				break;
			default:
				DRM_ERROR("unexpected release type\n");
				break;
			}
			id = next_id;

			qxl_release_free(qdev, release);
			++i;
		}
	}

	QXL_INFO(qdev, "%s: %lld\n", __func__, i);

	return i;
}

int qxl_alloc_bo_reserved(struct qxl_device *qdev, unsigned long size,
			  struct qxl_bo **_bo)
{
	struct qxl_bo *bo;
	int ret;

	ret = qxl_bo_create(qdev, size, false /* not kernel - device */,
			    QXL_GEM_DOMAIN_VRAM, NULL, &bo);
	if (ret) {
		DRM_ERROR("failed to allocate VRAM BO\n");
		return ret;
	}
	ret = qxl_bo_reserve(bo, false);
	if (unlikely(ret != 0))
		goto out_unref;

	*_bo = bo;
	return 0;
out_unref:
	qxl_bo_unref(&bo);
	return 0;
}

static int wait_for_io_cmd_user(struct qxl_device *qdev, uint8_t val, long port)
{
	int irq_num;
	long addr = qdev->io_base + port;
	int ret;

	mutex_lock(&qdev->async_io_mutex);
	irq_num = atomic_read(&qdev->irq_received_io_cmd);


	if (qdev->last_sent_io_cmd > irq_num) {
		ret = wait_event_interruptible(qdev->io_cmd_event,
					       atomic_read(&qdev->irq_received_io_cmd) > irq_num);
		if (ret)
			goto out;
		irq_num = atomic_read(&qdev->irq_received_io_cmd);
	}
	outb(val, addr);
	qdev->last_sent_io_cmd = irq_num + 1;
	ret = wait_event_interruptible(qdev->io_cmd_event,
				       atomic_read(&qdev->irq_received_io_cmd) > irq_num);
out:
	mutex_unlock(&qdev->async_io_mutex);
	return ret;
}

static void wait_for_io_cmd(struct qxl_device *qdev, uint8_t val, long port)
{
	int ret;

restart:
	ret = wait_for_io_cmd_user(qdev, val, port);
	if (ret == -ERESTARTSYS)
		goto restart;
}

int qxl_io_update_area(struct qxl_device *qdev, struct qxl_bo *surf,
			const struct qxl_rect *area)
{
	int surface_id;
	uint32_t surface_width, surface_height;
	int ret;

	if (!surf->hw_surf_alloc)
		DRM_ERROR("got io update area with no hw surface\n");

	if (surf->is_primary)
		surface_id = 0;
	else
		surface_id = surf->surface_id;
	surface_width = surf->surf.width;
	surface_height = surf->surf.height;

	if (area->left < 0 || area->top < 0 ||
	    area->right > surface_width || area->bottom > surface_height) {
		qxl_io_log(qdev, "%s: not doing area update for "
			   "%d, (%d,%d,%d,%d) (%d,%d)\n", __func__, surface_id, area->left,
			   area->top, area->right, area->bottom, surface_width, surface_height);
		return -EINVAL;
	}
	mutex_lock(&qdev->update_area_mutex);
	qdev->ram_header->update_area = *area;
	qdev->ram_header->update_surface = surface_id;
	ret = wait_for_io_cmd_user(qdev, 0, QXL_IO_UPDATE_AREA_ASYNC);
	mutex_unlock(&qdev->update_area_mutex);
	return ret;
}

void qxl_io_notify_oom(struct qxl_device *qdev)
{
	outb(0, qdev->io_base + QXL_IO_NOTIFY_OOM);
}

void qxl_io_flush_release(struct qxl_device *qdev)
{
	outb(0, qdev->io_base + QXL_IO_FLUSH_RELEASE);
}

void qxl_io_flush_surfaces(struct qxl_device *qdev)
{
	wait_for_io_cmd(qdev, 0, QXL_IO_FLUSH_SURFACES_ASYNC);
}


void qxl_io_destroy_primary(struct qxl_device *qdev)
{
	wait_for_io_cmd(qdev, 0, QXL_IO_DESTROY_PRIMARY_ASYNC);
}

void qxl_io_create_primary(struct qxl_device *qdev, unsigned width,
			   unsigned height, unsigned offset, struct qxl_bo *bo)
{
	struct qxl_surface_create *create;

	QXL_INFO(qdev, "%s: qdev %p, ram_header %p\n", __func__, qdev,
		 qdev->ram_header);
	create = &qdev->ram_header->create_surface;
	create->format = bo->surf.format;
	create->width = width;
	create->height = height;
	create->stride = bo->surf.stride;
	create->mem = qxl_bo_physical_address(qdev, bo, offset);

	QXL_INFO(qdev, "%s: mem = %llx, from %p\n", __func__, create->mem,
		 bo->kptr);

	create->flags = QXL_SURF_FLAG_KEEP_DATA;
	create->type = QXL_SURF_TYPE_PRIMARY;

	wait_for_io_cmd(qdev, 0, QXL_IO_CREATE_PRIMARY_ASYNC);
}

void qxl_io_memslot_add(struct qxl_device *qdev, uint8_t id)
{
	QXL_INFO(qdev, "qxl_memslot_add %d\n", id);
	wait_for_io_cmd(qdev, id, QXL_IO_MEMSLOT_ADD_ASYNC);
}

void qxl_io_log(struct qxl_device *qdev, const char *fmt, ...)
{
	va_list args;

	va_start(args, fmt);
	vsnprintf(qdev->ram_header->log_buf, QXL_LOG_BUF_SIZE, fmt, args);
	va_end(args);
	/*
	 * DO not do a DRM output here - this will call printk, which will
	 * call back into qxl for rendering (qxl_fb)
	 */
	outb(0, qdev->io_base + QXL_IO_LOG);
}

void qxl_io_reset(struct qxl_device *qdev)
{
	outb(0, qdev->io_base + QXL_IO_RESET);
}

void qxl_io_monitors_config(struct qxl_device *qdev)
{
	qxl_io_log(qdev, "%s: %d [%dx%d+%d+%d]\n", __func__,
		   qdev->monitors_config ?
		   qdev->monitors_config->count : -1,
		   qdev->monitors_config && qdev->monitors_config->count ?
		   qdev->monitors_config->heads[0].width : -1,
		   qdev->monitors_config && qdev->monitors_config->count ?
		   qdev->monitors_config->heads[0].height : -1,
		   qdev->monitors_config && qdev->monitors_config->count ?
		   qdev->monitors_config->heads[0].x : -1,
		   qdev->monitors_config && qdev->monitors_config->count ?
		   qdev->monitors_config->heads[0].y : -1
		   );

	wait_for_io_cmd(qdev, 0, QXL_IO_MONITORS_CONFIG_ASYNC);
}

int qxl_surface_id_alloc(struct qxl_device *qdev,
		      struct qxl_bo *surf)
{
	uint32_t handle;
	int idr_ret;
	int count = 0;
again:
	idr_preload(GFP_ATOMIC);
	spin_lock(&qdev->surf_id_idr_lock);
	idr_ret = idr_alloc(&qdev->surf_id_idr, NULL, 1, 0, GFP_NOWAIT);
	spin_unlock(&qdev->surf_id_idr_lock);
	idr_preload_end();
	if (idr_ret < 0)
		return idr_ret;
	handle = idr_ret;

	if (handle >= qdev->rom->n_surfaces) {
		count++;
		spin_lock(&qdev->surf_id_idr_lock);
		idr_remove(&qdev->surf_id_idr, handle);
		spin_unlock(&qdev->surf_id_idr_lock);
		qxl_reap_surface_id(qdev, 2);
		goto again;
	}
	surf->surface_id = handle;

	spin_lock(&qdev->surf_id_idr_lock);
	qdev->last_alloced_surf_id = handle;
	spin_unlock(&qdev->surf_id_idr_lock);
	return 0;
}

void qxl_surface_id_dealloc(struct qxl_device *qdev,
			    uint32_t surface_id)
{
	spin_lock(&qdev->surf_id_idr_lock);
	idr_remove(&qdev->surf_id_idr, surface_id);
	spin_unlock(&qdev->surf_id_idr_lock);
}

int qxl_hw_surface_alloc(struct qxl_device *qdev,
			 struct qxl_bo *surf,
			 struct ttm_mem_reg *new_mem)
{
	struct qxl_surface_cmd *cmd;
	struct qxl_release *release;
	int ret;

	if (surf->hw_surf_alloc)
		return 0;

	ret = qxl_alloc_surface_release_reserved(qdev, QXL_SURFACE_CMD_CREATE,
						 NULL,
						 &release);
	if (ret)
		return ret;

	cmd = (struct qxl_surface_cmd *)qxl_release_map(qdev, release);
	cmd->type = QXL_SURFACE_CMD_CREATE;
	cmd->u.surface_create.format = surf->surf.format;
	cmd->u.surface_create.width = surf->surf.width;
	cmd->u.surface_create.height = surf->surf.height;
	cmd->u.surface_create.stride = surf->surf.stride;
	if (new_mem) {
		int slot_id = surf->type == QXL_GEM_DOMAIN_VRAM ? qdev->main_mem_slot : qdev->surfaces_mem_slot;
		struct qxl_memslot *slot = &(qdev->mem_slots[slot_id]);

		/* TODO - need to hold one of the locks to read tbo.offset */
		cmd->u.surface_create.data = slot->high_bits;

		cmd->u.surface_create.data |= (new_mem->start << PAGE_SHIFT) + surf->tbo.bdev->man[new_mem->mem_type].gpu_offset;
	} else
		cmd->u.surface_create.data = qxl_bo_physical_address(qdev, surf, 0);
	cmd->surface_id = surf->surface_id;
	qxl_release_unmap(qdev, release, &cmd->release_info);

	surf->surf_create = release;

	/* no need to add a release to the fence for this bo,
	   since it is only released when we ask to destroy the surface
	   and it would never signal otherwise */
	qxl_fence_releaseable(qdev, release);

	qxl_push_command_ring_release(qdev, release, QXL_CMD_SURFACE, false);

	qxl_release_unreserve(qdev, release);

	surf->hw_surf_alloc = true;
	spin_lock(&qdev->surf_id_idr_lock);
	idr_replace(&qdev->surf_id_idr, surf, surf->surface_id);
	spin_unlock(&qdev->surf_id_idr_lock);
	return 0;
}

int qxl_hw_surface_dealloc(struct qxl_device *qdev,
			   struct qxl_bo *surf)
{
	struct qxl_surface_cmd *cmd;
	struct qxl_release *release;
	int ret;
	int id;

	if (!surf->hw_surf_alloc)
		return 0;

	ret = qxl_alloc_surface_release_reserved(qdev, QXL_SURFACE_CMD_DESTROY,
						 surf->surf_create,
						 &release);
	if (ret)
		return ret;

	surf->surf_create = NULL;
	/* remove the surface from the idr, but not the surface id yet */
	spin_lock(&qdev->surf_id_idr_lock);
	idr_replace(&qdev->surf_id_idr, NULL, surf->surface_id);
	spin_unlock(&qdev->surf_id_idr_lock);
	surf->hw_surf_alloc = false;

	id = surf->surface_id;
	surf->surface_id = 0;

	release->surface_release_id = id;
	cmd = (struct qxl_surface_cmd *)qxl_release_map(qdev, release);
	cmd->type = QXL_SURFACE_CMD_DESTROY;
	cmd->surface_id = id;
	qxl_release_unmap(qdev, release, &cmd->release_info);

	qxl_fence_releaseable(qdev, release);

	qxl_push_command_ring_release(qdev, release, QXL_CMD_SURFACE, false);

	qxl_release_unreserve(qdev, release);


	return 0;
}

int qxl_update_surface(struct qxl_device *qdev, struct qxl_bo *surf)
{
	struct qxl_rect rect;
	int ret;

	/* if we are evicting, we need to make sure the surface is up
	   to date */
	rect.left = 0;
	rect.right = surf->surf.width;
	rect.top = 0;
	rect.bottom = surf->surf.height;
retry:
	ret = qxl_io_update_area(qdev, surf, &rect);
	if (ret == -ERESTARTSYS)
		goto retry;
	return ret;
}

static void qxl_surface_evict_locked(struct qxl_device *qdev, struct qxl_bo *surf, bool do_update_area)
{
	/* no need to update area if we are just freeing the surface normally */
	if (do_update_area)
		qxl_update_surface(qdev, surf);

	/* nuke the surface id at the hw */
	qxl_hw_surface_dealloc(qdev, surf);
}

void qxl_surface_evict(struct qxl_device *qdev, struct qxl_bo *surf, bool do_update_area)
{
	mutex_lock(&qdev->surf_evict_mutex);
	qxl_surface_evict_locked(qdev, surf, do_update_area);
	mutex_unlock(&qdev->surf_evict_mutex);
}

static int qxl_reap_surf(struct qxl_device *qdev, struct qxl_bo *surf, bool stall)
{
	int ret;

	ret = qxl_bo_reserve(surf, false);
	if (ret == -EBUSY)
		return -EBUSY;

	if (surf->fence.num_active_releases > 0 && stall == false) {
		qxl_bo_unreserve(surf);
		return -EBUSY;
	}

	if (stall)
		mutex_unlock(&qdev->surf_evict_mutex);

	spin_lock(&surf->tbo.bdev->fence_lock);
	ret = ttm_bo_wait(&surf->tbo, true, true, !stall);
	spin_unlock(&surf->tbo.bdev->fence_lock);

	if (stall)
		mutex_lock(&qdev->surf_evict_mutex);
	if (ret == -EBUSY) {
		qxl_bo_unreserve(surf);
		return -EBUSY;
	}

	qxl_surface_evict_locked(qdev, surf, true);
	qxl_bo_unreserve(surf);
	return 0;
}

static int qxl_reap_surface_id(struct qxl_device *qdev, int max_to_reap)
{
	int num_reaped = 0;
	int i, ret;
	bool stall = false;
	int start = 0;

	mutex_lock(&qdev->surf_evict_mutex);
again:

	spin_lock(&qdev->surf_id_idr_lock);
	start = qdev->last_alloced_surf_id + 1;
	spin_unlock(&qdev->surf_id_idr_lock);

	for (i = start; i < start + qdev->rom->n_surfaces; i++) {
		void *objptr;
		int surfid = i % qdev->rom->n_surfaces;

		/* this avoids the case where the objects is in the
		   idr but has been evicted half way - its makes
		   the idr lookup atomic with the eviction */
		spin_lock(&qdev->surf_id_idr_lock);
		objptr = idr_find(&qdev->surf_id_idr, surfid);
		spin_unlock(&qdev->surf_id_idr_lock);

		if (!objptr)
			continue;

		ret = qxl_reap_surf(qdev, objptr, stall);
		if (ret == 0)
			num_reaped++;
		if (num_reaped >= max_to_reap)
			break;
	}
	if (num_reaped == 0 && stall == false) {
		stall = true;
		goto again;
	}

	mutex_unlock(&qdev->surf_evict_mutex);
	if (num_reaped) {
		usleep_range(500, 1000);
		qxl_queue_garbage_collect(qdev, true);
	}

	return 0;
}