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drm: Global atomic state handling
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1/*
2 * Copyright (C) 2014 Red Hat
3 * Copyright (C) 2014 Intel Corp.
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 * and/or sell copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be included in
13 * all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
19 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
20 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
21 * OTHER DEALINGS IN THE SOFTWARE.
22 *
23 * Authors:
24 * Rob Clark <robdclark@gmail.com>
25 * Daniel Vetter <daniel.vetter@ffwll.ch>
26 */
27
28
29#include <drm/drmP.h>
30#include <drm/drm_atomic.h>
31#include <drm/drm_plane_helper.h>
32
33static void kfree_state(struct drm_atomic_state *state)
34{
35 kfree(state->connectors);
36 kfree(state->connector_states);
37 kfree(state->crtcs);
38 kfree(state->crtc_states);
39 kfree(state->planes);
40 kfree(state->plane_states);
41 kfree(state);
42}
43
44/**
45 * drm_atomic_state_alloc - allocate atomic state
46 * @dev: DRM device
47 *
48 * This allocates an empty atomic state to track updates.
49 */
50struct drm_atomic_state *
51drm_atomic_state_alloc(struct drm_device *dev)
52{
53 struct drm_atomic_state *state;
54
55 state = kzalloc(sizeof(*state), GFP_KERNEL);
56 if (!state)
57 return NULL;
58
59 state->crtcs = kcalloc(dev->mode_config.num_crtc,
60 sizeof(*state->crtcs), GFP_KERNEL);
61 if (!state->crtcs)
62 goto fail;
63 state->crtc_states = kcalloc(dev->mode_config.num_crtc,
64 sizeof(*state->crtc_states), GFP_KERNEL);
65 if (!state->crtc_states)
66 goto fail;
67 state->planes = kcalloc(dev->mode_config.num_total_plane,
68 sizeof(*state->planes), GFP_KERNEL);
69 if (!state->planes)
70 goto fail;
71 state->plane_states = kcalloc(dev->mode_config.num_total_plane,
72 sizeof(*state->plane_states), GFP_KERNEL);
73 if (!state->plane_states)
74 goto fail;
75 state->connectors = kcalloc(dev->mode_config.num_connector,
76 sizeof(*state->connectors),
77 GFP_KERNEL);
78 if (!state->connectors)
79 goto fail;
80 state->connector_states = kcalloc(dev->mode_config.num_connector,
81 sizeof(*state->connector_states),
82 GFP_KERNEL);
83 if (!state->connector_states)
84 goto fail;
85
86 state->dev = dev;
87
88 DRM_DEBUG_KMS("Allocate atomic state %p\n", state);
89
90 return state;
91fail:
92 kfree_state(state);
93
94 return NULL;
95}
96EXPORT_SYMBOL(drm_atomic_state_alloc);
97
98/**
99 * drm_atomic_state_clear - clear state object
100 * @state: atomic state
101 *
102 * When the w/w mutex algorithm detects a deadlock we need to back off and drop
103 * all locks. So someone else could sneak in and change the current modeset
104 * configuration. Which means that all the state assembled in @state is no
105 * longer an atomic update to the current state, but to some arbitrary earlier
106 * state. Which could break assumptions the driver's ->atomic_check likely
107 * relies on.
108 *
109 * Hence we must clear all cached state and completely start over, using this
110 * function.
111 */
112void drm_atomic_state_clear(struct drm_atomic_state *state)
113{
114 struct drm_device *dev = state->dev;
115 int i;
116
117 DRM_DEBUG_KMS("Clearing atomic state %p\n", state);
118
119 for (i = 0; i < dev->mode_config.num_connector; i++) {
120 struct drm_connector *connector = state->connectors[i];
121
122 if (!connector)
123 continue;
124
125 connector->funcs->atomic_destroy_state(connector,
126 state->connector_states[i]);
127 }
128
129 for (i = 0; i < dev->mode_config.num_crtc; i++) {
130 struct drm_crtc *crtc = state->crtcs[i];
131
132 if (!crtc)
133 continue;
134
135 crtc->funcs->atomic_destroy_state(crtc,
136 state->crtc_states[i]);
137 }
138
139 for (i = 0; i < dev->mode_config.num_total_plane; i++) {
140 struct drm_plane *plane = state->planes[i];
141
142 if (!plane)
143 continue;
144
145 plane->funcs->atomic_destroy_state(plane,
146 state->plane_states[i]);
147 }
148}
149EXPORT_SYMBOL(drm_atomic_state_clear);
150
151/**
152 * drm_atomic_state_free - free all memory for an atomic state
153 * @state: atomic state to deallocate
154 *
155 * This frees all memory associated with an atomic state, including all the
156 * per-object state for planes, crtcs and connectors.
157 */
158void drm_atomic_state_free(struct drm_atomic_state *state)
159{
160 drm_atomic_state_clear(state);
161
162 DRM_DEBUG_KMS("Freeing atomic state %p\n", state);
163
164 kfree_state(state);
165}
166EXPORT_SYMBOL(drm_atomic_state_free);
167
168/**
169 * drm_atomic_get_crtc_state - get crtc state
170 * @state: global atomic state object
171 * @crtc: crtc to get state object for
172 *
173 * This function returns the crtc state for the given crtc, allocating it if
174 * needed. It will also grab the relevant crtc lock to make sure that the state
175 * is consistent.
176 *
177 * Returns:
178 *
179 * Either the allocated state or the error code encoded into the pointer. When
180 * the error is EDEADLK then the w/w mutex code has detected a deadlock and the
181 * entire atomic sequence must be restarted. All other errors are fatal.
182 */
183struct drm_crtc_state *
184drm_atomic_get_crtc_state(struct drm_atomic_state *state,
185 struct drm_crtc *crtc)
186{
187 int ret, index;
188 struct drm_crtc_state *crtc_state;
189
190 index = drm_crtc_index(crtc);
191
192 if (state->crtc_states[index])
193 return state->crtc_states[index];
194
195 ret = drm_modeset_lock(&crtc->mutex, state->acquire_ctx);
196 if (ret)
197 return ERR_PTR(ret);
198
199 crtc_state = crtc->funcs->atomic_duplicate_state(crtc);
200 if (!crtc_state)
201 return ERR_PTR(-ENOMEM);
202
203 state->crtc_states[index] = crtc_state;
204 state->crtcs[index] = crtc;
205 crtc_state->state = state;
206
207 DRM_DEBUG_KMS("Added [CRTC:%d] %p state to %p\n",
208 crtc->base.id, crtc_state, state);
209
210 return crtc_state;
211}
212EXPORT_SYMBOL(drm_atomic_get_crtc_state);
213
214/**
215 * drm_atomic_get_plane_state - get plane state
216 * @state: global atomic state object
217 * @plane: plane to get state object for
218 *
219 * This function returns the plane state for the given plane, allocating it if
220 * needed. It will also grab the relevant plane lock to make sure that the state
221 * is consistent.
222 *
223 * Returns:
224 *
225 * Either the allocated state or the error code encoded into the pointer. When
226 * the error is EDEADLK then the w/w mutex code has detected a deadlock and the
227 * entire atomic sequence must be restarted. All other errors are fatal.
228 */
229struct drm_plane_state *
230drm_atomic_get_plane_state(struct drm_atomic_state *state,
231 struct drm_plane *plane)
232{
233 int ret, index;
234 struct drm_plane_state *plane_state;
235
236 index = drm_plane_index(plane);
237
238 if (state->plane_states[index])
239 return state->plane_states[index];
240
241 /*
242 * TODO: We currently don't have per-plane mutexes. So instead of trying
243 * crazy tricks with deferring plane->crtc and hoping for the best just
244 * grab all crtc locks. Once we have per-plane locks we must update this
245 * to only take the plane mutex.
246 */
247 ret = drm_modeset_lock_all_crtcs(state->dev, state->acquire_ctx);
248 if (ret)
249 return ERR_PTR(ret);
250
251 plane_state = plane->funcs->atomic_duplicate_state(plane);
252 if (!plane_state)
253 return ERR_PTR(-ENOMEM);
254
255 state->plane_states[index] = plane_state;
256 state->planes[index] = plane;
257 plane_state->state = state;
258
259 DRM_DEBUG_KMS("Added [PLANE:%d] %p state to %p\n",
260 plane->base.id, plane_state, state);
261
262 if (plane_state->crtc) {
263 struct drm_crtc_state *crtc_state;
264
265 crtc_state = drm_atomic_get_crtc_state(state,
266 plane_state->crtc);
267 if (IS_ERR(crtc_state))
268 return ERR_CAST(crtc_state);
269 }
270
271 return plane_state;
272}
273EXPORT_SYMBOL(drm_atomic_get_plane_state);
274
275/**
276 * drm_atomic_get_connector_state - get connector state
277 * @state: global atomic state object
278 * @connector: connector to get state object for
279 *
280 * This function returns the connector state for the given connector,
281 * allocating it if needed. It will also grab the relevant connector lock to
282 * make sure that the state is consistent.
283 *
284 * Returns:
285 *
286 * Either the allocated state or the error code encoded into the pointer. When
287 * the error is EDEADLK then the w/w mutex code has detected a deadlock and the
288 * entire atomic sequence must be restarted. All other errors are fatal.
289 */
290struct drm_connector_state *
291drm_atomic_get_connector_state(struct drm_atomic_state *state,
292 struct drm_connector *connector)
293{
294 int ret, index;
295 struct drm_mode_config *config = &connector->dev->mode_config;
296 struct drm_connector_state *connector_state;
297
298 index = drm_connector_index(connector);
299
300 if (state->connector_states[index])
301 return state->connector_states[index];
302
303 ret = drm_modeset_lock(&config->connection_mutex, state->acquire_ctx);
304 if (ret)
305 return ERR_PTR(ret);
306
307 connector_state = connector->funcs->atomic_duplicate_state(connector);
308 if (!connector_state)
309 return ERR_PTR(-ENOMEM);
310
311 state->connector_states[index] = connector_state;
312 state->connectors[index] = connector;
313 connector_state->state = state;
314
315 DRM_DEBUG_KMS("Added [CONNECTOR:%d] %p state to %p\n",
316 connector->base.id, connector_state, state);
317
318 if (connector_state->crtc) {
319 struct drm_crtc_state *crtc_state;
320
321 crtc_state = drm_atomic_get_crtc_state(state,
322 connector_state->crtc);
323 if (IS_ERR(crtc_state))
324 return ERR_CAST(crtc_state);
325 }
326
327 return connector_state;
328}
329EXPORT_SYMBOL(drm_atomic_get_connector_state);
330
331/**
332 * drm_atomic_set_crtc_for_plane - set crtc for plane
333 * @plane_state: atomic state object for the plane
334 * @crtc: crtc to use for the plane
335 *
336 * Changing the assigned crtc for a plane requires us to grab the lock and state
337 * for the new crtc, as needed. This function takes care of all these details
338 * besides updating the pointer in the state object itself.
339 *
340 * Returns:
341 * 0 on success or can fail with -EDEADLK or -ENOMEM. When the error is EDEADLK
342 * then the w/w mutex code has detected a deadlock and the entire atomic
343 * sequence must be restarted. All other errors are fatal.
344 */
345int
346drm_atomic_set_crtc_for_plane(struct drm_plane_state *plane_state,
347 struct drm_crtc *crtc)
348{
349 struct drm_crtc_state *crtc_state;
350
351 if (crtc) {
352 crtc_state = drm_atomic_get_crtc_state(plane_state->state,
353 crtc);
354 if (IS_ERR(crtc_state))
355 return PTR_ERR(crtc_state);
356 }
357
358 plane_state->crtc = crtc;
359
360 if (crtc)
361 DRM_DEBUG_KMS("Link plane state %p to [CRTC:%d]\n",
362 plane_state, crtc->base.id);
363 else
364 DRM_DEBUG_KMS("Link plane state %p to [NOCRTC]\n", plane_state);
365
366 return 0;
367}
368EXPORT_SYMBOL(drm_atomic_set_crtc_for_plane);
369
370/**
371 * drm_atomic_set_crtc_for_connector - set crtc for connector
372 * @conn_state: atomic state object for the connector
373 * @crtc: crtc to use for the connector
374 *
375 * Changing the assigned crtc for a connector requires us to grab the lock and
376 * state for the new crtc, as needed. This function takes care of all these
377 * details besides updating the pointer in the state object itself.
378 *
379 * Returns:
380 * 0 on success or can fail with -EDEADLK or -ENOMEM. When the error is EDEADLK
381 * then the w/w mutex code has detected a deadlock and the entire atomic
382 * sequence must be restarted. All other errors are fatal.
383 */
384int
385drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state,
386 struct drm_crtc *crtc)
387{
388 struct drm_crtc_state *crtc_state;
389
390 if (crtc) {
391 crtc_state = drm_atomic_get_crtc_state(conn_state->state, crtc);
392 if (IS_ERR(crtc_state))
393 return PTR_ERR(crtc_state);
394 }
395
396 conn_state->crtc = crtc;
397
398 if (crtc)
399 DRM_DEBUG_KMS("Link connector state %p to [CRTC:%d]\n",
400 conn_state, crtc->base.id);
401 else
402 DRM_DEBUG_KMS("Link connector state %p to [NOCRTC]\n",
403 conn_state);
404
405 return 0;
406}
407EXPORT_SYMBOL(drm_atomic_set_crtc_for_connector);
408
409/**
410 * drm_atomic_add_affected_connectors - add connectors for crtc
411 * @state: atomic state
412 * @crtc: DRM crtc
413 *
414 * This function walks the current configuration and adds all connectors
415 * currently using @crtc to the atomic configuration @state. Note that this
416 * function must acquire the connection mutex. This can potentially cause
417 * unneeded seralization if the update is just for the planes on one crtc. Hence
418 * drivers and helpers should only call this when really needed (e.g. when a
419 * full modeset needs to happen due to some change).
420 *
421 * Returns:
422 * 0 on success or can fail with -EDEADLK or -ENOMEM. When the error is EDEADLK
423 * then the w/w mutex code has detected a deadlock and the entire atomic
424 * sequence must be restarted. All other errors are fatal.
425 */
426int
427drm_atomic_add_affected_connectors(struct drm_atomic_state *state,
428 struct drm_crtc *crtc)
429{
430 struct drm_mode_config *config = &state->dev->mode_config;
431 struct drm_connector *connector;
432 struct drm_connector_state *conn_state;
433 int ret;
434
435 ret = drm_modeset_lock(&config->connection_mutex, state->acquire_ctx);
436 if (ret)
437 return ret;
438
439 DRM_DEBUG_KMS("Adding all current connectors for [CRTC:%d] to %p\n",
440 crtc->base.id, state);
441
442 /*
443 * Changed connectors are already in @state, so only need to look at the
444 * current configuration.
445 */
446 list_for_each_entry(connector, &config->connector_list, head) {
447 if (connector->state->crtc != crtc)
448 continue;
449
450 conn_state = drm_atomic_get_connector_state(state, connector);
451 if (IS_ERR(conn_state))
452 return PTR_ERR(conn_state);
453 }
454
455 return 0;
456}
457EXPORT_SYMBOL(drm_atomic_add_affected_connectors);
458
459/**
460 * drm_atomic_connectors_for_crtc - count number of connected outputs
461 * @state: atomic state
462 * @crtc: DRM crtc
463 *
464 * This function counts all connectors which will be connected to @crtc
465 * according to @state. Useful to recompute the enable state for @crtc.
466 */
467int
468drm_atomic_connectors_for_crtc(struct drm_atomic_state *state,
469 struct drm_crtc *crtc)
470{
471 int nconnectors = state->dev->mode_config.num_connector;
472 int i, num_connected_connectors = 0;
473
474 for (i = 0; i < nconnectors; i++) {
475 struct drm_connector_state *conn_state;
476
477 conn_state = state->connector_states[i];
478
479 if (conn_state && conn_state->crtc == crtc)
480 num_connected_connectors++;
481 }
482
483 DRM_DEBUG_KMS("State %p has %i connectors for [CRTC:%d]\n",
484 state, num_connected_connectors, crtc->base.id);
485
486 return num_connected_connectors;
487}
488EXPORT_SYMBOL(drm_atomic_connectors_for_crtc);
489
490/**
491 * drm_atomic_legacy_backoff - locking backoff for legacy ioctls
492 * @state: atomic state
493 *
494 * This function should be used by legacy entry points which don't understand
495 * -EDEADLK semantics. For simplicity this one will grab all modeset locks after
496 * the slowpath completed.
497 */
498void drm_atomic_legacy_backoff(struct drm_atomic_state *state)
499{
500 int ret;
501
502retry:
503 drm_modeset_backoff(state->acquire_ctx);
504
505 ret = drm_modeset_lock(&state->dev->mode_config.connection_mutex,
506 state->acquire_ctx);
507 if (ret)
508 goto retry;
509 ret = drm_modeset_lock_all_crtcs(state->dev,
510 state->acquire_ctx);
511 if (ret)
512 goto retry;
513}
514EXPORT_SYMBOL(drm_atomic_legacy_backoff);
515
516/**
517 * drm_atomic_check_only - check whether a given config would work
518 * @state: atomic configuration to check
519 *
520 * Note that this function can return -EDEADLK if the driver needed to acquire
521 * more locks but encountered a deadlock. The caller must then do the usual w/w
522 * backoff dance and restart. All other errors are fatal.
523 *
524 * Returns:
525 * 0 on success, negative error code on failure.
526 */
527int drm_atomic_check_only(struct drm_atomic_state *state)
528{
529 struct drm_mode_config *config = &state->dev->mode_config;
530
531 DRM_DEBUG_KMS("checking %p\n", state);
532
533 if (config->funcs->atomic_check)
534 return config->funcs->atomic_check(state->dev, state);
535 else
536 return 0;
537}
538EXPORT_SYMBOL(drm_atomic_check_only);
539
540/**
541 * drm_atomic_commit - commit configuration atomically
542 * @state: atomic configuration to check
543 *
544 * Note that this function can return -EDEADLK if the driver needed to acquire
545 * more locks but encountered a deadlock. The caller must then do the usual w/w
546 * backoff dance and restart. All other errors are fatal.
547 *
548 * Also note that on successful execution ownership of @state is transferred
549 * from the caller of this function to the function itself. The caller must not
550 * free or in any other way access @state. If the function fails then the caller
551 * must clean up @state itself.
552 *
553 * Returns:
554 * 0 on success, negative error code on failure.
555 */
556int drm_atomic_commit(struct drm_atomic_state *state)
557{
558 struct drm_mode_config *config = &state->dev->mode_config;
559 int ret;
560
561 ret = drm_atomic_check_only(state);
562 if (ret)
563 return ret;
564
565 DRM_DEBUG_KMS("commiting %p\n", state);
566
567 return config->funcs->atomic_commit(state->dev, state, false);
568}
569EXPORT_SYMBOL(drm_atomic_commit);
570
571/**
572 * drm_atomic_async_commit - atomic&async configuration commit
573 * @state: atomic configuration to check
574 *
575 * Note that this function can return -EDEADLK if the driver needed to acquire
576 * more locks but encountered a deadlock. The caller must then do the usual w/w
577 * backoff dance and restart. All other errors are fatal.
578 *
579 * Also note that on successful execution ownership of @state is transferred
580 * from the caller of this function to the function itself. The caller must not
581 * free or in any other way access @state. If the function fails then the caller
582 * must clean up @state itself.
583 *
584 * Returns:
585 * 0 on success, negative error code on failure.
586 */
587int drm_atomic_async_commit(struct drm_atomic_state *state)
588{
589 struct drm_mode_config *config = &state->dev->mode_config;
590 int ret;
591
592 ret = drm_atomic_check_only(state);
593 if (ret)
594 return ret;
595
596 DRM_DEBUG_KMS("commiting %p asynchronously\n", state);
597
598 return config->funcs->atomic_commit(state->dev, state, true);
599}
600EXPORT_SYMBOL(drm_atomic_async_commit);