1/*
2 * Copyright © 2006 Keith Packard
3 * Copyright © 2007-2008 Dave Airlie
4 * Copyright © 2007-2008 Intel Corporation
5 * Jesse Barnes <jesse.barnes@intel.com>
6 * Copyright © 2011-2013 Intel Corporation
7 * Copyright © 2015 Intel Corporation
8 * Daniel Vetter <daniel.vetter@ffwll.ch>
9 *
10 * Permission is hereby granted, free of charge, to any person obtaining a
11 * copy of this software and associated documentation files (the "Software"),
12 * to deal in the Software without restriction, including without limitation
13 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
14 * and/or sell copies of the Software, and to permit persons to whom the
15 * Software is furnished to do so, subject to the following conditions:
16 *
17 * The above copyright notice and this permission notice shall be included in
18 * all copies or substantial portions of the Software.
19 *
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
23 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
24 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
25 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
26 * OTHER DEALINGS IN THE SOFTWARE.
27 */
28
29#ifndef __DRM_MODESET_HELPER_VTABLES_H__
30#define __DRM_MODESET_HELPER_VTABLES_H__
31
32#include <drm/drm_crtc.h>
33#include <drm/drm_encoder.h>
34
35/**
36 * DOC: overview
37 *
38 * The DRM mode setting helper functions are common code for drivers to use if
39 * they wish. Drivers are not forced to use this code in their
40 * implementations but it would be useful if the code they do use at least
41 * provides a consistent interface and operation to userspace. Therefore it is
42 * highly recommended to use the provided helpers as much as possible.
43 *
44 * Because there is only one pointer per modeset object to hold a vfunc table
45 * for helper libraries they are by necessity shared among the different
46 * helpers.
47 *
48 * To make this clear all the helper vtables are pulled together in this location here.
49 */
50
51struct drm_writeback_connector;
52struct drm_writeback_job;
53
54enum mode_set_atomic {
55 LEAVE_ATOMIC_MODE_SET,
56 ENTER_ATOMIC_MODE_SET,
57};
58
59/**
60 * struct drm_crtc_helper_funcs - helper operations for CRTCs
61 *
62 * These hooks are used by the legacy CRTC helpers and the new atomic
63 * modesetting helpers.
64 */
65struct drm_crtc_helper_funcs {
66 /**
67 * @dpms:
68 *
69 * Callback to control power levels on the CRTC. If the mode passed in
70 * is unsupported, the provider must use the next lowest power level.
71 * This is used by the legacy CRTC helpers to implement DPMS
72 * functionality in drm_helper_connector_dpms().
73 *
74 * This callback is also used to disable a CRTC by calling it with
75 * DRM_MODE_DPMS_OFF if the @disable hook isn't used.
76 *
77 * This callback is used by the legacy CRTC helpers. Atomic helpers
78 * also support using this hook for enabling and disabling a CRTC to
79 * facilitate transitions to atomic, but it is deprecated. Instead
80 * @atomic_enable and @atomic_disable should be used.
81 */
82 void (*dpms)(struct drm_crtc *crtc, int mode);
83
84 /**
85 * @prepare:
86 *
87 * This callback should prepare the CRTC for a subsequent modeset, which
88 * in practice means the driver should disable the CRTC if it is
89 * running. Most drivers ended up implementing this by calling their
90 * @dpms hook with DRM_MODE_DPMS_OFF.
91 *
92 * This callback is used by the legacy CRTC helpers. Atomic helpers
93 * also support using this hook for disabling a CRTC to facilitate
94 * transitions to atomic, but it is deprecated. Instead @atomic_disable
95 * should be used.
96 */
97 void (*prepare)(struct drm_crtc *crtc);
98
99 /**
100 * @commit:
101 *
102 * This callback should commit the new mode on the CRTC after a modeset,
103 * which in practice means the driver should enable the CRTC. Most
104 * drivers ended up implementing this by calling their @dpms hook with
105 * DRM_MODE_DPMS_ON.
106 *
107 * This callback is used by the legacy CRTC helpers. Atomic helpers
108 * also support using this hook for enabling a CRTC to facilitate
109 * transitions to atomic, but it is deprecated. Instead @atomic_enable
110 * should be used.
111 */
112 void (*commit)(struct drm_crtc *crtc);
113
114 /**
115 * @mode_valid:
116 *
117 * This callback is used to check if a specific mode is valid in this
118 * crtc. This should be implemented if the crtc has some sort of
119 * restriction in the modes it can display. For example, a given crtc
120 * may be responsible to set a clock value. If the clock can not
121 * produce all the values for the available modes then this callback
122 * can be used to restrict the number of modes to only the ones that
123 * can be displayed.
124 *
125 * This hook is used by the probe helpers to filter the mode list in
126 * drm_helper_probe_single_connector_modes(), and it is used by the
127 * atomic helpers to validate modes supplied by userspace in
128 * drm_atomic_helper_check_modeset().
129 *
130 * This function is optional.
131 *
132 * NOTE:
133 *
134 * Since this function is both called from the check phase of an atomic
135 * commit, and the mode validation in the probe paths it is not allowed
136 * to look at anything else but the passed-in mode, and validate it
137 * against configuration-invariant hardware constraints. Any further
138 * limits which depend upon the configuration can only be checked in
139 * @mode_fixup or @atomic_check.
140 *
141 * RETURNS:
142 *
143 * drm_mode_status Enum
144 */
145 enum drm_mode_status (*mode_valid)(struct drm_crtc *crtc,
146 const struct drm_display_mode *mode);
147
148 /**
149 * @mode_fixup:
150 *
151 * This callback is used to validate a mode. The parameter mode is the
152 * display mode that userspace requested, adjusted_mode is the mode the
153 * encoders need to be fed with. Note that this is the inverse semantics
154 * of the meaning for the &drm_encoder and &drm_bridge_funcs.mode_fixup
155 * vfunc. If the CRTC cannot support the requested conversion from mode
156 * to adjusted_mode it should reject the modeset. See also
157 * &drm_crtc_state.adjusted_mode for more details.
158 *
159 * This function is used by both legacy CRTC helpers and atomic helpers.
160 * With atomic helpers it is optional.
161 *
162 * NOTE:
163 *
164 * This function is called in the check phase of atomic modesets, which
165 * can be aborted for any reason (including on userspace's request to
166 * just check whether a configuration would be possible). Atomic drivers
167 * MUST NOT touch any persistent state (hardware or software) or data
168 * structures except the passed in adjusted_mode parameter.
169 *
170 * This is in contrast to the legacy CRTC helpers where this was
171 * allowed.
172 *
173 * Atomic drivers which need to inspect and adjust more state should
174 * instead use the @atomic_check callback, but note that they're not
175 * perfectly equivalent: @mode_valid is called from
176 * drm_atomic_helper_check_modeset(), but @atomic_check is called from
177 * drm_atomic_helper_check_planes(), because originally it was meant for
178 * plane update checks only.
179 *
180 * Also beware that userspace can request its own custom modes, neither
181 * core nor helpers filter modes to the list of probe modes reported by
182 * the GETCONNECTOR IOCTL and stored in &drm_connector.modes. To ensure
183 * that modes are filtered consistently put any CRTC constraints and
184 * limits checks into @mode_valid.
185 *
186 * RETURNS:
187 *
188 * True if an acceptable configuration is possible, false if the modeset
189 * operation should be rejected.
190 */
191 bool (*mode_fixup)(struct drm_crtc *crtc,
192 const struct drm_display_mode *mode,
193 struct drm_display_mode *adjusted_mode);
194
195 /**
196 * @mode_set:
197 *
198 * This callback is used by the legacy CRTC helpers to set a new mode,
199 * position and framebuffer. Since it ties the primary plane to every
200 * mode change it is incompatible with universal plane support. And
201 * since it can't update other planes it's incompatible with atomic
202 * modeset support.
203 *
204 * This callback is only used by CRTC helpers and deprecated.
205 *
206 * RETURNS:
207 *
208 * 0 on success or a negative error code on failure.
209 */
210 int (*mode_set)(struct drm_crtc *crtc, struct drm_display_mode *mode,
211 struct drm_display_mode *adjusted_mode, int x, int y,
212 struct drm_framebuffer *old_fb);
213
214 /**
215 * @mode_set_nofb:
216 *
217 * This callback is used to update the display mode of a CRTC without
218 * changing anything of the primary plane configuration. This fits the
219 * requirement of atomic and hence is used by the atomic helpers.
220 *
221 * Note that the display pipe is completely off when this function is
222 * called. Atomic drivers which need hardware to be running before they
223 * program the new display mode (e.g. because they implement runtime PM)
224 * should not use this hook. This is because the helper library calls
225 * this hook only once per mode change and not every time the display
226 * pipeline is suspended using either DPMS or the new "ACTIVE" property.
227 * Which means register values set in this callback might get reset when
228 * the CRTC is suspended, but not restored. Such drivers should instead
229 * move all their CRTC setup into the @atomic_enable callback.
230 *
231 * This callback is optional.
232 */
233 void (*mode_set_nofb)(struct drm_crtc *crtc);
234
235 /**
236 * @mode_set_base:
237 *
238 * This callback is used by the legacy CRTC helpers to set a new
239 * framebuffer and scanout position. It is optional and used as an
240 * optimized fast-path instead of a full mode set operation with all the
241 * resulting flickering. If it is not present
242 * drm_crtc_helper_set_config() will fall back to a full modeset, using
243 * the @mode_set callback. Since it can't update other planes it's
244 * incompatible with atomic modeset support.
245 *
246 * This callback is only used by the CRTC helpers and deprecated.
247 *
248 * RETURNS:
249 *
250 * 0 on success or a negative error code on failure.
251 */
252 int (*mode_set_base)(struct drm_crtc *crtc, int x, int y,
253 struct drm_framebuffer *old_fb);
254
255 /**
256 * @mode_set_base_atomic:
257 *
258 * This callback is used by the fbdev helpers to set a new framebuffer
259 * and scanout without sleeping, i.e. from an atomic calling context. It
260 * is only used to implement kgdb support.
261 *
262 * This callback is optional and only needed for kgdb support in the fbdev
263 * helpers.
264 *
265 * RETURNS:
266 *
267 * 0 on success or a negative error code on failure.
268 */
269 int (*mode_set_base_atomic)(struct drm_crtc *crtc,
270 struct drm_framebuffer *fb, int x, int y,
271 enum mode_set_atomic);
272
273 /**
274 * @disable:
275 *
276 * This callback should be used to disable the CRTC. With the atomic
277 * drivers it is called after all encoders connected to this CRTC have
278 * been shut off already using their own
279 * &drm_encoder_helper_funcs.disable hook. If that sequence is too
280 * simple drivers can just add their own hooks and call it from this
281 * CRTC callback here by looping over all encoders connected to it using
282 * for_each_encoder_on_crtc().
283 *
284 * This hook is used both by legacy CRTC helpers and atomic helpers.
285 * Atomic drivers don't need to implement it if there's no need to
286 * disable anything at the CRTC level. To ensure that runtime PM
287 * handling (using either DPMS or the new "ACTIVE" property) works
288 * @disable must be the inverse of @atomic_enable for atomic drivers.
289 * Atomic drivers should consider to use @atomic_disable instead of
290 * this one.
291 *
292 * NOTE:
293 *
294 * With legacy CRTC helpers there's a big semantic difference between
295 * @disable and other hooks (like @prepare or @dpms) used to shut down a
296 * CRTC: @disable is only called when also logically disabling the
297 * display pipeline and needs to release any resources acquired in
298 * @mode_set (like shared PLLs, or again release pinned framebuffers).
299 *
300 * Therefore @disable must be the inverse of @mode_set plus @commit for
301 * drivers still using legacy CRTC helpers, which is different from the
302 * rules under atomic.
303 */
304 void (*disable)(struct drm_crtc *crtc);
305
306 /**
307 * @atomic_check:
308 *
309 * Drivers should check plane-update related CRTC constraints in this
310 * hook. They can also check mode related limitations but need to be
311 * aware of the calling order, since this hook is used by
312 * drm_atomic_helper_check_planes() whereas the preparations needed to
313 * check output routing and the display mode is done in
314 * drm_atomic_helper_check_modeset(). Therefore drivers that want to
315 * check output routing and display mode constraints in this callback
316 * must ensure that drm_atomic_helper_check_modeset() has been called
317 * beforehand. This is calling order used by the default helper
318 * implementation in drm_atomic_helper_check().
319 *
320 * When using drm_atomic_helper_check_planes() this hook is called
321 * after the &drm_plane_helper_funcs.atomic_check hook for planes, which
322 * allows drivers to assign shared resources requested by planes in this
323 * callback here. For more complicated dependencies the driver can call
324 * the provided check helpers multiple times until the computed state
325 * has a final configuration and everything has been checked.
326 *
327 * This function is also allowed to inspect any other object's state and
328 * can add more state objects to the atomic commit if needed. Care must
329 * be taken though to ensure that state check and compute functions for
330 * these added states are all called, and derived state in other objects
331 * all updated. Again the recommendation is to just call check helpers
332 * until a maximal configuration is reached.
333 *
334 * This callback is used by the atomic modeset helpers, but it is
335 * optional.
336 *
337 * NOTE:
338 *
339 * This function is called in the check phase of an atomic update. The
340 * driver is not allowed to change anything outside of the free-standing
341 * state object passed-in.
342 *
343 * Also beware that userspace can request its own custom modes, neither
344 * core nor helpers filter modes to the list of probe modes reported by
345 * the GETCONNECTOR IOCTL and stored in &drm_connector.modes. To ensure
346 * that modes are filtered consistently put any CRTC constraints and
347 * limits checks into @mode_valid.
348 *
349 * RETURNS:
350 *
351 * 0 on success, -EINVAL if the state or the transition can't be
352 * supported, -ENOMEM on memory allocation failure and -EDEADLK if an
353 * attempt to obtain another state object ran into a &drm_modeset_lock
354 * deadlock.
355 */
356 int (*atomic_check)(struct drm_crtc *crtc,
357 struct drm_atomic_state *state);
358
359 /**
360 * @atomic_begin:
361 *
362 * Drivers should prepare for an atomic update of multiple planes on
363 * a CRTC in this hook. Depending upon hardware this might be vblank
364 * evasion, blocking updates by setting bits or doing preparatory work
365 * for e.g. manual update display.
366 *
367 * This hook is called before any plane commit functions are called.
368 *
369 * Note that the power state of the display pipe when this function is
370 * called depends upon the exact helpers and calling sequence the driver
371 * has picked. See drm_atomic_helper_commit_planes() for a discussion of
372 * the tradeoffs and variants of plane commit helpers.
373 *
374 * This callback is used by the atomic modeset helpers, but it is
375 * optional.
376 */
377 void (*atomic_begin)(struct drm_crtc *crtc,
378 struct drm_atomic_state *state);
379 /**
380 * @atomic_flush:
381 *
382 * Drivers should finalize an atomic update of multiple planes on
383 * a CRTC in this hook. Depending upon hardware this might include
384 * checking that vblank evasion was successful, unblocking updates by
385 * setting bits or setting the GO bit to flush out all updates.
386 *
387 * Simple hardware or hardware with special requirements can commit and
388 * flush out all updates for all planes from this hook and forgo all the
389 * other commit hooks for plane updates.
390 *
391 * This hook is called after any plane commit functions are called.
392 *
393 * Note that the power state of the display pipe when this function is
394 * called depends upon the exact helpers and calling sequence the driver
395 * has picked. See drm_atomic_helper_commit_planes() for a discussion of
396 * the tradeoffs and variants of plane commit helpers.
397 *
398 * This callback is used by the atomic modeset helpers, but it is
399 * optional.
400 */
401 void (*atomic_flush)(struct drm_crtc *crtc,
402 struct drm_atomic_state *state);
403
404 /**
405 * @atomic_enable:
406 *
407 * This callback should be used to enable the CRTC. With the atomic
408 * drivers it is called before all encoders connected to this CRTC are
409 * enabled through the encoder's own &drm_encoder_helper_funcs.enable
410 * hook. If that sequence is too simple drivers can just add their own
411 * hooks and call it from this CRTC callback here by looping over all
412 * encoders connected to it using for_each_encoder_on_crtc().
413 *
414 * This hook is used only by atomic helpers, for symmetry with
415 * @atomic_disable. Atomic drivers don't need to implement it if there's
416 * no need to enable anything at the CRTC level. To ensure that runtime
417 * PM handling (using either DPMS or the new "ACTIVE" property) works
418 * @atomic_enable must be the inverse of @atomic_disable for atomic
419 * drivers.
420 *
421 * This function is optional.
422 */
423 void (*atomic_enable)(struct drm_crtc *crtc,
424 struct drm_atomic_state *state);
425
426 /**
427 * @atomic_disable:
428 *
429 * This callback should be used to disable the CRTC. With the atomic
430 * drivers it is called after all encoders connected to this CRTC have
431 * been shut off already using their own
432 * &drm_encoder_helper_funcs.disable hook. If that sequence is too
433 * simple drivers can just add their own hooks and call it from this
434 * CRTC callback here by looping over all encoders connected to it using
435 * for_each_encoder_on_crtc().
436 *
437 * This hook is used only by atomic helpers. Atomic drivers don't
438 * need to implement it if there's no need to disable anything at the
439 * CRTC level.
440 *
441 * This function is optional.
442 */
443 void (*atomic_disable)(struct drm_crtc *crtc,
444 struct drm_atomic_state *state);
445
446 /**
447 * @get_scanout_position:
448 *
449 * Called by vblank timestamping code.
450 *
451 * Returns the current display scanout position from a CRTC and an
452 * optional accurate ktime_get() timestamp of when the position was
453 * measured. Note that this is a helper callback which is only used
454 * if a driver uses drm_crtc_vblank_helper_get_vblank_timestamp()
455 * for the @drm_crtc_funcs.get_vblank_timestamp callback.
456 *
457 * Parameters:
458 *
459 * crtc:
460 * The CRTC.
461 * in_vblank_irq:
462 * True when called from drm_crtc_handle_vblank(). Some drivers
463 * need to apply some workarounds for gpu-specific vblank irq
464 * quirks if the flag is set.
465 * vpos:
466 * Target location for current vertical scanout position.
467 * hpos:
468 * Target location for current horizontal scanout position.
469 * stime:
470 * Target location for timestamp taken immediately before
471 * scanout position query. Can be NULL to skip timestamp.
472 * etime:
473 * Target location for timestamp taken immediately after
474 * scanout position query. Can be NULL to skip timestamp.
475 * mode:
476 * Current display timings.
477 *
478 * Returns vpos as a positive number while in active scanout area.
479 * Returns vpos as a negative number inside vblank, counting the number
480 * of scanlines to go until end of vblank, e.g., -1 means "one scanline
481 * until start of active scanout / end of vblank."
482 *
483 * Returns:
484 *
485 * True on success, false if a reliable scanout position counter could
486 * not be read out.
487 */
488 bool (*get_scanout_position)(struct drm_crtc *crtc,
489 bool in_vblank_irq, int *vpos, int *hpos,
490 ktime_t *stime, ktime_t *etime,
491 const struct drm_display_mode *mode);
492};
493
494/**
495 * drm_crtc_helper_add - sets the helper vtable for a crtc
496 * @crtc: DRM CRTC
497 * @funcs: helper vtable to set for @crtc
498 */
499static inline void drm_crtc_helper_add(struct drm_crtc *crtc,
500 const struct drm_crtc_helper_funcs *funcs)
501{
502 crtc->helper_private = funcs;
503}
504
505/**
506 * struct drm_encoder_helper_funcs - helper operations for encoders
507 *
508 * These hooks are used by the legacy CRTC helpers and the new atomic
509 * modesetting helpers.
510 */
511struct drm_encoder_helper_funcs {
512 /**
513 * @dpms:
514 *
515 * Callback to control power levels on the encoder. If the mode passed in
516 * is unsupported, the provider must use the next lowest power level.
517 * This is used by the legacy encoder helpers to implement DPMS
518 * functionality in drm_helper_connector_dpms().
519 *
520 * This callback is also used to disable an encoder by calling it with
521 * DRM_MODE_DPMS_OFF if the @disable hook isn't used.
522 *
523 * This callback is used by the legacy CRTC helpers. Atomic helpers
524 * also support using this hook for enabling and disabling an encoder to
525 * facilitate transitions to atomic, but it is deprecated. Instead
526 * @enable and @disable should be used.
527 */
528 void (*dpms)(struct drm_encoder *encoder, int mode);
529
530 /**
531 * @mode_valid:
532 *
533 * This callback is used to check if a specific mode is valid in this
534 * encoder. This should be implemented if the encoder has some sort
535 * of restriction in the modes it can display. For example, a given
536 * encoder may be responsible to set a clock value. If the clock can
537 * not produce all the values for the available modes then this callback
538 * can be used to restrict the number of modes to only the ones that
539 * can be displayed.
540 *
541 * This hook is used by the probe helpers to filter the mode list in
542 * drm_helper_probe_single_connector_modes(), and it is used by the
543 * atomic helpers to validate modes supplied by userspace in
544 * drm_atomic_helper_check_modeset().
545 *
546 * This function is optional.
547 *
548 * NOTE:
549 *
550 * Since this function is both called from the check phase of an atomic
551 * commit, and the mode validation in the probe paths it is not allowed
552 * to look at anything else but the passed-in mode, and validate it
553 * against configuration-invariant hardware constraints. Any further
554 * limits which depend upon the configuration can only be checked in
555 * @mode_fixup or @atomic_check.
556 *
557 * RETURNS:
558 *
559 * drm_mode_status Enum
560 */
561 enum drm_mode_status (*mode_valid)(struct drm_encoder *crtc,
562 const struct drm_display_mode *mode);
563
564 /**
565 * @mode_fixup:
566 *
567 * This callback is used to validate and adjust a mode. The parameter
568 * mode is the display mode that should be fed to the next element in
569 * the display chain, either the final &drm_connector or a &drm_bridge.
570 * The parameter adjusted_mode is the input mode the encoder requires. It
571 * can be modified by this callback and does not need to match mode. See
572 * also &drm_crtc_state.adjusted_mode for more details.
573 *
574 * This function is used by both legacy CRTC helpers and atomic helpers.
575 * This hook is optional.
576 *
577 * NOTE:
578 *
579 * This function is called in the check phase of atomic modesets, which
580 * can be aborted for any reason (including on userspace's request to
581 * just check whether a configuration would be possible). Atomic drivers
582 * MUST NOT touch any persistent state (hardware or software) or data
583 * structures except the passed in adjusted_mode parameter.
584 *
585 * This is in contrast to the legacy CRTC helpers where this was
586 * allowed.
587 *
588 * Atomic drivers which need to inspect and adjust more state should
589 * instead use the @atomic_check callback. If @atomic_check is used,
590 * this hook isn't called since @atomic_check allows a strict superset
591 * of the functionality of @mode_fixup.
592 *
593 * Also beware that userspace can request its own custom modes, neither
594 * core nor helpers filter modes to the list of probe modes reported by
595 * the GETCONNECTOR IOCTL and stored in &drm_connector.modes. To ensure
596 * that modes are filtered consistently put any encoder constraints and
597 * limits checks into @mode_valid.
598 *
599 * RETURNS:
600 *
601 * True if an acceptable configuration is possible, false if the modeset
602 * operation should be rejected.
603 */
604 bool (*mode_fixup)(struct drm_encoder *encoder,
605 const struct drm_display_mode *mode,
606 struct drm_display_mode *adjusted_mode);
607
608 /**
609 * @prepare:
610 *
611 * This callback should prepare the encoder for a subsequent modeset,
612 * which in practice means the driver should disable the encoder if it
613 * is running. Most drivers ended up implementing this by calling their
614 * @dpms hook with DRM_MODE_DPMS_OFF.
615 *
616 * This callback is used by the legacy CRTC helpers. Atomic helpers
617 * also support using this hook for disabling an encoder to facilitate
618 * transitions to atomic, but it is deprecated. Instead @disable should
619 * be used.
620 */
621 void (*prepare)(struct drm_encoder *encoder);
622
623 /**
624 * @commit:
625 *
626 * This callback should commit the new mode on the encoder after a modeset,
627 * which in practice means the driver should enable the encoder. Most
628 * drivers ended up implementing this by calling their @dpms hook with
629 * DRM_MODE_DPMS_ON.
630 *
631 * This callback is used by the legacy CRTC helpers. Atomic helpers
632 * also support using this hook for enabling an encoder to facilitate
633 * transitions to atomic, but it is deprecated. Instead @enable should
634 * be used.
635 */
636 void (*commit)(struct drm_encoder *encoder);
637
638 /**
639 * @mode_set:
640 *
641 * This callback is used to update the display mode of an encoder.
642 *
643 * Note that the display pipe is completely off when this function is
644 * called. Drivers which need hardware to be running before they program
645 * the new display mode (because they implement runtime PM) should not
646 * use this hook, because the helper library calls it only once and not
647 * every time the display pipeline is suspend using either DPMS or the
648 * new "ACTIVE" property. Such drivers should instead move all their
649 * encoder setup into the @enable callback.
650 *
651 * This callback is used both by the legacy CRTC helpers and the atomic
652 * modeset helpers. It is optional in the atomic helpers.
653 *
654 * NOTE:
655 *
656 * If the driver uses the atomic modeset helpers and needs to inspect
657 * the connector state or connector display info during mode setting,
658 * @atomic_mode_set can be used instead.
659 */
660 void (*mode_set)(struct drm_encoder *encoder,
661 struct drm_display_mode *mode,
662 struct drm_display_mode *adjusted_mode);
663
664 /**
665 * @atomic_mode_set:
666 *
667 * This callback is used to update the display mode of an encoder.
668 *
669 * Note that the display pipe is completely off when this function is
670 * called. Drivers which need hardware to be running before they program
671 * the new display mode (because they implement runtime PM) should not
672 * use this hook, because the helper library calls it only once and not
673 * every time the display pipeline is suspended using either DPMS or the
674 * new "ACTIVE" property. Such drivers should instead move all their
675 * encoder setup into the @enable callback.
676 *
677 * This callback is used by the atomic modeset helpers in place of the
678 * @mode_set callback, if set by the driver. It is optional and should
679 * be used instead of @mode_set if the driver needs to inspect the
680 * connector state or display info, since there is no direct way to
681 * go from the encoder to the current connector.
682 */
683 void (*atomic_mode_set)(struct drm_encoder *encoder,
684 struct drm_crtc_state *crtc_state,
685 struct drm_connector_state *conn_state);
686
687 /**
688 * @detect:
689 *
690 * This callback can be used by drivers who want to do detection on the
691 * encoder object instead of in connector functions.
692 *
693 * It is not used by any helper and therefore has purely driver-specific
694 * semantics. New drivers shouldn't use this and instead just implement
695 * their own private callbacks.
696 *
697 * FIXME:
698 *
699 * This should just be converted into a pile of driver vfuncs.
700 * Currently radeon, amdgpu and nouveau are using it.
701 */
702 enum drm_connector_status (*detect)(struct drm_encoder *encoder,
703 struct drm_connector *connector);
704
705 /**
706 * @atomic_disable:
707 *
708 * This callback should be used to disable the encoder. With the atomic
709 * drivers it is called before this encoder's CRTC has been shut off
710 * using their own &drm_crtc_helper_funcs.atomic_disable hook. If that
711 * sequence is too simple drivers can just add their own driver private
712 * encoder hooks and call them from CRTC's callback by looping over all
713 * encoders connected to it using for_each_encoder_on_crtc().
714 *
715 * This callback is a variant of @disable that provides the atomic state
716 * to the driver. If @atomic_disable is implemented, @disable is not
717 * called by the helpers.
718 *
719 * This hook is only used by atomic helpers. Atomic drivers don't need
720 * to implement it if there's no need to disable anything at the encoder
721 * level. To ensure that runtime PM handling (using either DPMS or the
722 * new "ACTIVE" property) works @atomic_disable must be the inverse of
723 * @atomic_enable.
724 */
725 void (*atomic_disable)(struct drm_encoder *encoder,
726 struct drm_atomic_state *state);
727
728 /**
729 * @atomic_enable:
730 *
731 * This callback should be used to enable the encoder. It is called
732 * after this encoder's CRTC has been enabled using their own
733 * &drm_crtc_helper_funcs.atomic_enable hook. If that sequence is
734 * too simple drivers can just add their own driver private encoder
735 * hooks and call them from CRTC's callback by looping over all encoders
736 * connected to it using for_each_encoder_on_crtc().
737 *
738 * This callback is a variant of @enable that provides the atomic state
739 * to the driver. If @atomic_enable is implemented, @enable is not
740 * called by the helpers.
741 *
742 * This hook is only used by atomic helpers, it is the opposite of
743 * @atomic_disable. Atomic drivers don't need to implement it if there's
744 * no need to enable anything at the encoder level. To ensure that
745 * runtime PM handling works @atomic_enable must be the inverse of
746 * @atomic_disable.
747 */
748 void (*atomic_enable)(struct drm_encoder *encoder,
749 struct drm_atomic_state *state);
750
751 /**
752 * @disable:
753 *
754 * This callback should be used to disable the encoder. With the atomic
755 * drivers it is called before this encoder's CRTC has been shut off
756 * using their own &drm_crtc_helper_funcs.disable hook. If that
757 * sequence is too simple drivers can just add their own driver private
758 * encoder hooks and call them from CRTC's callback by looping over all
759 * encoders connected to it using for_each_encoder_on_crtc().
760 *
761 * This hook is used both by legacy CRTC helpers and atomic helpers.
762 * Atomic drivers don't need to implement it if there's no need to
763 * disable anything at the encoder level. To ensure that runtime PM
764 * handling (using either DPMS or the new "ACTIVE" property) works
765 * @disable must be the inverse of @enable for atomic drivers.
766 *
767 * For atomic drivers also consider @atomic_disable and save yourself
768 * from having to read the NOTE below!
769 *
770 * NOTE:
771 *
772 * With legacy CRTC helpers there's a big semantic difference between
773 * @disable and other hooks (like @prepare or @dpms) used to shut down a
774 * encoder: @disable is only called when also logically disabling the
775 * display pipeline and needs to release any resources acquired in
776 * @mode_set (like shared PLLs, or again release pinned framebuffers).
777 *
778 * Therefore @disable must be the inverse of @mode_set plus @commit for
779 * drivers still using legacy CRTC helpers, which is different from the
780 * rules under atomic.
781 */
782 void (*disable)(struct drm_encoder *encoder);
783
784 /**
785 * @enable:
786 *
787 * This callback should be used to enable the encoder. With the atomic
788 * drivers it is called after this encoder's CRTC has been enabled using
789 * their own &drm_crtc_helper_funcs.enable hook. If that sequence is
790 * too simple drivers can just add their own driver private encoder
791 * hooks and call them from CRTC's callback by looping over all encoders
792 * connected to it using for_each_encoder_on_crtc().
793 *
794 * This hook is only used by atomic helpers, it is the opposite of
795 * @disable. Atomic drivers don't need to implement it if there's no
796 * need to enable anything at the encoder level. To ensure that
797 * runtime PM handling (using either DPMS or the new "ACTIVE" property)
798 * works @enable must be the inverse of @disable for atomic drivers.
799 */
800 void (*enable)(struct drm_encoder *encoder);
801
802 /**
803 * @atomic_check:
804 *
805 * This callback is used to validate encoder state for atomic drivers.
806 * Since the encoder is the object connecting the CRTC and connector it
807 * gets passed both states, to be able to validate interactions and
808 * update the CRTC to match what the encoder needs for the requested
809 * connector.
810 *
811 * Since this provides a strict superset of the functionality of
812 * @mode_fixup (the requested and adjusted modes are both available
813 * through the passed in &struct drm_crtc_state) @mode_fixup is not
814 * called when @atomic_check is implemented.
815 *
816 * This function is used by the atomic helpers, but it is optional.
817 *
818 * NOTE:
819 *
820 * This function is called in the check phase of an atomic update. The
821 * driver is not allowed to change anything outside of the free-standing
822 * state objects passed-in or assembled in the overall &drm_atomic_state
823 * update tracking structure.
824 *
825 * Also beware that userspace can request its own custom modes, neither
826 * core nor helpers filter modes to the list of probe modes reported by
827 * the GETCONNECTOR IOCTL and stored in &drm_connector.modes. To ensure
828 * that modes are filtered consistently put any encoder constraints and
829 * limits checks into @mode_valid.
830 *
831 * RETURNS:
832 *
833 * 0 on success, -EINVAL if the state or the transition can't be
834 * supported, -ENOMEM on memory allocation failure and -EDEADLK if an
835 * attempt to obtain another state object ran into a &drm_modeset_lock
836 * deadlock.
837 */
838 int (*atomic_check)(struct drm_encoder *encoder,
839 struct drm_crtc_state *crtc_state,
840 struct drm_connector_state *conn_state);
841};
842
843/**
844 * drm_encoder_helper_add - sets the helper vtable for an encoder
845 * @encoder: DRM encoder
846 * @funcs: helper vtable to set for @encoder
847 */
848static inline void drm_encoder_helper_add(struct drm_encoder *encoder,
849 const struct drm_encoder_helper_funcs *funcs)
850{
851 encoder->helper_private = funcs;
852}
853
854/**
855 * struct drm_connector_helper_funcs - helper operations for connectors
856 *
857 * These functions are used by the atomic and legacy modeset helpers and by the
858 * probe helpers.
859 */
860struct drm_connector_helper_funcs {
861 /**
862 * @get_modes:
863 *
864 * This function should fill in all modes currently valid for the sink
865 * into the &drm_connector.probed_modes list. It should also update the
866 * EDID property by calling drm_connector_update_edid_property().
867 *
868 * The usual way to implement this is to cache the EDID retrieved in the
869 * probe callback somewhere in the driver-private connector structure.
870 * In this function drivers then parse the modes in the EDID and add
871 * them by calling drm_add_edid_modes(). But connectors that drive a
872 * fixed panel can also manually add specific modes using
873 * drm_mode_probed_add(). Drivers which manually add modes should also
874 * make sure that the &drm_connector.display_info,
875 * &drm_connector.width_mm and &drm_connector.height_mm fields are
876 * filled in.
877 *
878 * Note that the caller function will automatically add standard VESA
879 * DMT modes up to 1024x768 if the .get_modes() helper operation returns
880 * no mode and if the connector status is connector_status_connected or
881 * connector_status_unknown. There is no need to call
882 * drm_add_modes_noedid() manually in that case.
883 *
884 * Virtual drivers that just want some standard VESA mode with a given
885 * resolution can call drm_add_modes_noedid(), and mark the preferred
886 * one using drm_set_preferred_mode().
887 *
888 * This function is only called after the @detect hook has indicated
889 * that a sink is connected and when the EDID isn't overridden through
890 * sysfs or the kernel commandline.
891 *
892 * This callback is used by the probe helpers in e.g.
893 * drm_helper_probe_single_connector_modes().
894 *
895 * To avoid races with concurrent connector state updates, the helper
896 * libraries always call this with the &drm_mode_config.connection_mutex
897 * held. Because of this it's safe to inspect &drm_connector->state.
898 *
899 * RETURNS:
900 *
901 * The number of modes added by calling drm_mode_probed_add(). Return 0
902 * on failures (no modes) instead of negative error codes.
903 */
904 int (*get_modes)(struct drm_connector *connector);
905
906 /**
907 * @detect_ctx:
908 *
909 * Check to see if anything is attached to the connector. The parameter
910 * force is set to false whilst polling, true when checking the
911 * connector due to a user request. force can be used by the driver to
912 * avoid expensive, destructive operations during automated probing.
913 *
914 * This callback is optional, if not implemented the connector will be
915 * considered as always being attached.
916 *
917 * This is the atomic version of &drm_connector_funcs.detect.
918 *
919 * To avoid races against concurrent connector state updates, the
920 * helper libraries always call this with ctx set to a valid context,
921 * and &drm_mode_config.connection_mutex will always be locked with
922 * the ctx parameter set to this ctx. This allows taking additional
923 * locks as required.
924 *
925 * RETURNS:
926 *
927 * &drm_connector_status indicating the connector's status,
928 * or the error code returned by drm_modeset_lock(), -EDEADLK.
929 */
930 int (*detect_ctx)(struct drm_connector *connector,
931 struct drm_modeset_acquire_ctx *ctx,
932 bool force);
933
934 /**
935 * @mode_valid:
936 *
937 * Callback to validate a mode for a connector, irrespective of the
938 * specific display configuration.
939 *
940 * This callback is used by the probe helpers to filter the mode list
941 * (which is usually derived from the EDID data block from the sink).
942 * See e.g. drm_helper_probe_single_connector_modes().
943 *
944 * This function is optional.
945 *
946 * NOTE:
947 *
948 * This only filters the mode list supplied to userspace in the
949 * GETCONNECTOR IOCTL. Compared to &drm_encoder_helper_funcs.mode_valid,
950 * &drm_crtc_helper_funcs.mode_valid and &drm_bridge_funcs.mode_valid,
951 * which are also called by the atomic helpers from
952 * drm_atomic_helper_check_modeset(). This allows userspace to force and
953 * ignore sink constraint (like the pixel clock limits in the screen's
954 * EDID), which is useful for e.g. testing, or working around a broken
955 * EDID. Any source hardware constraint (which always need to be
956 * enforced) therefore should be checked in one of the above callbacks,
957 * and not this one here.
958 *
959 * To avoid races with concurrent connector state updates, the helper
960 * libraries always call this with the &drm_mode_config.connection_mutex
961 * held. Because of this it's safe to inspect &drm_connector->state.
962 *
963 * RETURNS:
964 *
965 * Either &drm_mode_status.MODE_OK or one of the failure reasons in &enum
966 * drm_mode_status.
967 */
968 enum drm_mode_status (*mode_valid)(struct drm_connector *connector,
969 struct drm_display_mode *mode);
970
971 /**
972 * @mode_valid_ctx:
973 *
974 * Callback to validate a mode for a connector, irrespective of the
975 * specific display configuration.
976 *
977 * This callback is used by the probe helpers to filter the mode list
978 * (which is usually derived from the EDID data block from the sink).
979 * See e.g. drm_helper_probe_single_connector_modes().
980 *
981 * This function is optional, and is the atomic version of
982 * &drm_connector_helper_funcs.mode_valid.
983 *
984 * To allow for accessing the atomic state of modesetting objects, the
985 * helper libraries always call this with ctx set to a valid context,
986 * and &drm_mode_config.connection_mutex will always be locked with
987 * the ctx parameter set to @ctx. This allows for taking additional
988 * locks as required.
989 *
990 * Even though additional locks may be acquired, this callback is
991 * still expected not to take any constraints into account which would
992 * be influenced by the currently set display state - such constraints
993 * should be handled in the driver's atomic check. For example, if a
994 * connector shares display bandwidth with other connectors then it
995 * would be ok to validate the minimum bandwidth requirement of a mode
996 * against the maximum possible bandwidth of the connector. But it
997 * wouldn't be ok to take the current bandwidth usage of other
998 * connectors into account, as this would change depending on the
999 * display state.
1000 *
1001 * Returns:
1002 * 0 if &drm_connector_helper_funcs.mode_valid_ctx succeeded and wrote
1003 * the &enum drm_mode_status value to @status, or a negative error
1004 * code otherwise.
1005 *
1006 */
1007 int (*mode_valid_ctx)(struct drm_connector *connector,
1008 struct drm_display_mode *mode,
1009 struct drm_modeset_acquire_ctx *ctx,
1010 enum drm_mode_status *status);
1011
1012 /**
1013 * @best_encoder:
1014 *
1015 * This function should select the best encoder for the given connector.
1016 *
1017 * This function is used by both the atomic helpers (in the
1018 * drm_atomic_helper_check_modeset() function) and in the legacy CRTC
1019 * helpers.
1020 *
1021 * NOTE:
1022 *
1023 * In atomic drivers this function is called in the check phase of an
1024 * atomic update. The driver is not allowed to change or inspect
1025 * anything outside of arguments passed-in. Atomic drivers which need to
1026 * inspect dynamic configuration state should instead use
1027 * @atomic_best_encoder.
1028 *
1029 * You can leave this function to NULL if the connector is only
1030 * attached to a single encoder. In this case, the core will call
1031 * drm_connector_get_single_encoder() for you.
1032 *
1033 * RETURNS:
1034 *
1035 * Encoder that should be used for the given connector and connector
1036 * state, or NULL if no suitable encoder exists. Note that the helpers
1037 * will ensure that encoders aren't used twice, drivers should not check
1038 * for this.
1039 */
1040 struct drm_encoder *(*best_encoder)(struct drm_connector *connector);
1041
1042 /**
1043 * @atomic_best_encoder:
1044 *
1045 * This is the atomic version of @best_encoder for atomic drivers which
1046 * need to select the best encoder depending upon the desired
1047 * configuration and can't select it statically.
1048 *
1049 * This function is used by drm_atomic_helper_check_modeset().
1050 * If it is not implemented, the core will fallback to @best_encoder
1051 * (or drm_connector_get_single_encoder() if @best_encoder is NULL).
1052 *
1053 * NOTE:
1054 *
1055 * This function is called in the check phase of an atomic update. The
1056 * driver is not allowed to change anything outside of the
1057 * &drm_atomic_state update tracking structure passed in.
1058 *
1059 * RETURNS:
1060 *
1061 * Encoder that should be used for the given connector and connector
1062 * state, or NULL if no suitable encoder exists. Note that the helpers
1063 * will ensure that encoders aren't used twice, drivers should not check
1064 * for this.
1065 */
1066 struct drm_encoder *(*atomic_best_encoder)(struct drm_connector *connector,
1067 struct drm_atomic_state *state);
1068
1069 /**
1070 * @atomic_check:
1071 *
1072 * This hook is used to validate connector state. This function is
1073 * called from &drm_atomic_helper_check_modeset, and is called when
1074 * a connector property is set, or a modeset on the crtc is forced.
1075 *
1076 * Because &drm_atomic_helper_check_modeset may be called multiple times,
1077 * this function should handle being called multiple times as well.
1078 *
1079 * This function is also allowed to inspect any other object's state and
1080 * can add more state objects to the atomic commit if needed. Care must
1081 * be taken though to ensure that state check and compute functions for
1082 * these added states are all called, and derived state in other objects
1083 * all updated. Again the recommendation is to just call check helpers
1084 * until a maximal configuration is reached.
1085 *
1086 * NOTE:
1087 *
1088 * This function is called in the check phase of an atomic update. The
1089 * driver is not allowed to change anything outside of the free-standing
1090 * state objects passed-in or assembled in the overall &drm_atomic_state
1091 * update tracking structure.
1092 *
1093 * RETURNS:
1094 *
1095 * 0 on success, -EINVAL if the state or the transition can't be
1096 * supported, -ENOMEM on memory allocation failure and -EDEADLK if an
1097 * attempt to obtain another state object ran into a &drm_modeset_lock
1098 * deadlock.
1099 */
1100 int (*atomic_check)(struct drm_connector *connector,
1101 struct drm_atomic_state *state);
1102
1103 /**
1104 * @atomic_commit:
1105 *
1106 * This hook is to be used by drivers implementing writeback connectors
1107 * that need a point when to commit the writeback job to the hardware.
1108 * The writeback_job to commit is available in the new connector state,
1109 * in &drm_connector_state.writeback_job.
1110 *
1111 * This hook is optional.
1112 *
1113 * This callback is used by the atomic modeset helpers.
1114 */
1115 void (*atomic_commit)(struct drm_connector *connector,
1116 struct drm_atomic_state *state);
1117
1118 /**
1119 * @prepare_writeback_job:
1120 *
1121 * As writeback jobs contain a framebuffer, drivers may need to
1122 * prepare and clean them up the same way they can prepare and
1123 * clean up framebuffers for planes. This optional connector operation
1124 * is used to support the preparation of writeback jobs. The job
1125 * prepare operation is called from drm_atomic_helper_prepare_planes()
1126 * for struct &drm_writeback_connector connectors only.
1127 *
1128 * This operation is optional.
1129 *
1130 * This callback is used by the atomic modeset helpers.
1131 */
1132 int (*prepare_writeback_job)(struct drm_writeback_connector *connector,
1133 struct drm_writeback_job *job);
1134 /**
1135 * @cleanup_writeback_job:
1136 *
1137 * This optional connector operation is used to support the
1138 * cleanup of writeback jobs. The job cleanup operation is called
1139 * from the existing drm_writeback_cleanup_job() function, invoked
1140 * both when destroying the job as part of an aborted commit, or when
1141 * the job completes.
1142 *
1143 * This operation is optional.
1144 *
1145 * This callback is used by the atomic modeset helpers.
1146 */
1147 void (*cleanup_writeback_job)(struct drm_writeback_connector *connector,
1148 struct drm_writeback_job *job);
1149
1150 /**
1151 * @enable_hpd:
1152 *
1153 * Enable hot-plug detection for the connector.
1154 *
1155 * This operation is optional.
1156 *
1157 * This callback is used by the drm_kms_helper_poll_enable() helpers.
1158 *
1159 * This operation does not need to perform any hpd state tracking as
1160 * the DRM core handles that maintenance and ensures the calls to enable
1161 * and disable hpd are balanced.
1162 *
1163 */
1164 void (*enable_hpd)(struct drm_connector *connector);
1165
1166 /**
1167 * @disable_hpd:
1168 *
1169 * Disable hot-plug detection for the connector.
1170 *
1171 * This operation is optional.
1172 *
1173 * This callback is used by the drm_kms_helper_poll_disable() helpers.
1174 *
1175 * This operation does not need to perform any hpd state tracking as
1176 * the DRM core handles that maintenance and ensures the calls to enable
1177 * and disable hpd are balanced.
1178 *
1179 */
1180 void (*disable_hpd)(struct drm_connector *connector);
1181};
1182
1183/**
1184 * drm_connector_helper_add - sets the helper vtable for a connector
1185 * @connector: DRM connector
1186 * @funcs: helper vtable to set for @connector
1187 */
1188static inline void drm_connector_helper_add(struct drm_connector *connector,
1189 const struct drm_connector_helper_funcs *funcs)
1190{
1191 connector->helper_private = funcs;
1192}
1193
1194/**
1195 * struct drm_plane_helper_funcs - helper operations for planes
1196 *
1197 * These functions are used by the atomic helpers.
1198 */
1199struct drm_plane_helper_funcs {
1200 /**
1201 * @prepare_fb:
1202 *
1203 * This hook is to prepare a framebuffer for scanout by e.g. pinning
1204 * its backing storage or relocating it into a contiguous block of
1205 * VRAM. Other possible preparatory work includes flushing caches.
1206 *
1207 * This function must not block for outstanding rendering, since it is
1208 * called in the context of the atomic IOCTL even for async commits to
1209 * be able to return any errors to userspace. Instead the recommended
1210 * way is to fill out the &drm_plane_state.fence of the passed-in
1211 * &drm_plane_state. If the driver doesn't support native fences then
1212 * equivalent functionality should be implemented through private
1213 * members in the plane structure.
1214 *
1215 * For GEM drivers who neither have a @prepare_fb nor @cleanup_fb hook
1216 * set drm_gem_plane_helper_prepare_fb() is called automatically to
1217 * implement this. Other drivers which need additional plane processing
1218 * can call drm_gem_plane_helper_prepare_fb() from their @prepare_fb
1219 * hook.
1220 *
1221 * The resources acquired in @prepare_fb persist after the end of
1222 * the atomic commit. Resources that can be release at the commit's end
1223 * should be acquired in @begin_fb_access and released in @end_fb_access.
1224 * For example, a GEM buffer's pin operation belongs into @prepare_fb to
1225 * keep the buffer pinned after the commit. But a vmap operation for
1226 * shadow-plane helpers belongs into @begin_fb_access, so that atomic
1227 * helpers remove the mapping at the end of the commit.
1228 *
1229 * The helpers will call @cleanup_fb with matching arguments for every
1230 * successful call to this hook.
1231 *
1232 * This callback is used by the atomic modeset helpers, but it is
1233 * optional. See @begin_fb_access for preparing per-commit resources.
1234 *
1235 * RETURNS:
1236 *
1237 * 0 on success or one of the following negative error codes allowed by
1238 * the &drm_mode_config_funcs.atomic_commit vfunc. When using helpers
1239 * this callback is the only one which can fail an atomic commit,
1240 * everything else must complete successfully.
1241 */
1242 int (*prepare_fb)(struct drm_plane *plane,
1243 struct drm_plane_state *new_state);
1244 /**
1245 * @cleanup_fb:
1246 *
1247 * This hook is called to clean up any resources allocated for the given
1248 * framebuffer and plane configuration in @prepare_fb.
1249 *
1250 * This callback is used by the atomic modeset helpers, but it is
1251 * optional.
1252 */
1253 void (*cleanup_fb)(struct drm_plane *plane,
1254 struct drm_plane_state *old_state);
1255
1256 /**
1257 * @begin_fb_access:
1258 *
1259 * This hook prepares the plane for access during an atomic commit.
1260 * In contrast to @prepare_fb, resources acquired in @begin_fb_access,
1261 * are released at the end of the atomic commit in @end_fb_access.
1262 *
1263 * For example, with shadow-plane helpers, the GEM buffer's vmap
1264 * operation belongs into @begin_fb_access, so that the buffer's
1265 * memory will be unmapped at the end of the commit in @end_fb_access.
1266 * But a GEM buffer's pin operation belongs into @prepare_fb
1267 * to keep the buffer pinned after the commit.
1268 *
1269 * The callback is used by the atomic modeset helpers, but it is optional.
1270 * See @end_fb_cleanup for undoing the effects of @begin_fb_access and
1271 * @prepare_fb for acquiring resources until the next pageflip.
1272 *
1273 * Returns:
1274 * 0 on success, or a negative errno code otherwise.
1275 */
1276 int (*begin_fb_access)(struct drm_plane *plane, struct drm_plane_state *new_plane_state);
1277
1278 /**
1279 * @end_fb_access:
1280 *
1281 * This hook cleans up resources allocated by @begin_fb_access. It it called
1282 * at the end of a commit for the new plane state.
1283 */
1284 void (*end_fb_access)(struct drm_plane *plane, struct drm_plane_state *new_plane_state);
1285
1286 /**
1287 * @atomic_check:
1288 *
1289 * Drivers should check plane specific constraints in this hook.
1290 *
1291 * When using drm_atomic_helper_check_planes() plane's @atomic_check
1292 * hooks are called before the ones for CRTCs, which allows drivers to
1293 * request shared resources that the CRTC controls here. For more
1294 * complicated dependencies the driver can call the provided check helpers
1295 * multiple times until the computed state has a final configuration and
1296 * everything has been checked.
1297 *
1298 * This function is also allowed to inspect any other object's state and
1299 * can add more state objects to the atomic commit if needed. Care must
1300 * be taken though to ensure that state check and compute functions for
1301 * these added states are all called, and derived state in other objects
1302 * all updated. Again the recommendation is to just call check helpers
1303 * until a maximal configuration is reached.
1304 *
1305 * This callback is used by the atomic modeset helpers, but it is
1306 * optional.
1307 *
1308 * NOTE:
1309 *
1310 * This function is called in the check phase of an atomic update. The
1311 * driver is not allowed to change anything outside of the
1312 * &drm_atomic_state update tracking structure.
1313 *
1314 * RETURNS:
1315 *
1316 * 0 on success, -EINVAL if the state or the transition can't be
1317 * supported, -ENOMEM on memory allocation failure and -EDEADLK if an
1318 * attempt to obtain another state object ran into a &drm_modeset_lock
1319 * deadlock.
1320 */
1321 int (*atomic_check)(struct drm_plane *plane,
1322 struct drm_atomic_state *state);
1323
1324 /**
1325 * @atomic_update:
1326 *
1327 * Drivers should use this function to update the plane state. This
1328 * hook is called in-between the &drm_crtc_helper_funcs.atomic_begin and
1329 * drm_crtc_helper_funcs.atomic_flush callbacks.
1330 *
1331 * Note that the power state of the display pipe when this function is
1332 * called depends upon the exact helpers and calling sequence the driver
1333 * has picked. See drm_atomic_helper_commit_planes() for a discussion of
1334 * the tradeoffs and variants of plane commit helpers.
1335 *
1336 * This callback is used by the atomic modeset helpers, but it is optional.
1337 */
1338 void (*atomic_update)(struct drm_plane *plane,
1339 struct drm_atomic_state *state);
1340
1341 /**
1342 * @atomic_enable:
1343 *
1344 * Drivers should use this function to unconditionally enable a plane.
1345 * This hook is called in-between the &drm_crtc_helper_funcs.atomic_begin
1346 * and drm_crtc_helper_funcs.atomic_flush callbacks. It is called after
1347 * @atomic_update, which will be called for all enabled planes. Drivers
1348 * that use @atomic_enable should set up a plane in @atomic_update and
1349 * afterwards enable the plane in @atomic_enable. If a plane needs to be
1350 * enabled before installing the scanout buffer, drivers can still do
1351 * so in @atomic_update.
1352 *
1353 * Note that the power state of the display pipe when this function is
1354 * called depends upon the exact helpers and calling sequence the driver
1355 * has picked. See drm_atomic_helper_commit_planes() for a discussion of
1356 * the tradeoffs and variants of plane commit helpers.
1357 *
1358 * This callback is used by the atomic modeset helpers, but it is
1359 * optional. If implemented, @atomic_enable should be the inverse of
1360 * @atomic_disable. Drivers that don't want to use either can still
1361 * implement the complete plane update in @atomic_update.
1362 */
1363 void (*atomic_enable)(struct drm_plane *plane,
1364 struct drm_atomic_state *state);
1365
1366 /**
1367 * @atomic_disable:
1368 *
1369 * Drivers should use this function to unconditionally disable a plane.
1370 * This hook is called in-between the
1371 * &drm_crtc_helper_funcs.atomic_begin and
1372 * drm_crtc_helper_funcs.atomic_flush callbacks. It is an alternative to
1373 * @atomic_update, which will be called for disabling planes, too, if
1374 * the @atomic_disable hook isn't implemented.
1375 *
1376 * This hook is also useful to disable planes in preparation of a modeset,
1377 * by calling drm_atomic_helper_disable_planes_on_crtc() from the
1378 * &drm_crtc_helper_funcs.disable hook.
1379 *
1380 * Note that the power state of the display pipe when this function is
1381 * called depends upon the exact helpers and calling sequence the driver
1382 * has picked. See drm_atomic_helper_commit_planes() for a discussion of
1383 * the tradeoffs and variants of plane commit helpers.
1384 *
1385 * This callback is used by the atomic modeset helpers, but it is
1386 * optional. It's intended to reverse the effects of @atomic_enable.
1387 */
1388 void (*atomic_disable)(struct drm_plane *plane,
1389 struct drm_atomic_state *state);
1390
1391 /**
1392 * @atomic_async_check:
1393 *
1394 * Drivers should set this function pointer to check if the plane's
1395 * atomic state can be updated in a async fashion. Here async means
1396 * "not vblank synchronized".
1397 *
1398 * This hook is called by drm_atomic_async_check() to establish if a
1399 * given update can be committed asynchronously, that is, if it can
1400 * jump ahead of the state currently queued for update.
1401 *
1402 * RETURNS:
1403 *
1404 * Return 0 on success and any error returned indicates that the update
1405 * can not be applied in asynchronous manner.
1406 */
1407 int (*atomic_async_check)(struct drm_plane *plane,
1408 struct drm_atomic_state *state);
1409
1410 /**
1411 * @atomic_async_update:
1412 *
1413 * Drivers should set this function pointer to perform asynchronous
1414 * updates of planes, that is, jump ahead of the currently queued
1415 * state and update the plane. Here async means "not vblank
1416 * synchronized".
1417 *
1418 * This hook is called by drm_atomic_helper_async_commit().
1419 *
1420 * An async update will happen on legacy cursor updates. An async
1421 * update won't happen if there is an outstanding commit modifying
1422 * the same plane.
1423 *
1424 * When doing async_update drivers shouldn't replace the
1425 * &drm_plane_state but update the current one with the new plane
1426 * configurations in the new plane_state.
1427 *
1428 * Drivers should also swap the framebuffers between current plane
1429 * state (&drm_plane.state) and new_state.
1430 * This is required since cleanup for async commits is performed on
1431 * the new state, rather than old state like for traditional commits.
1432 * Since we want to give up the reference on the current (old) fb
1433 * instead of our brand new one, swap them in the driver during the
1434 * async commit.
1435 *
1436 * FIXME:
1437 * - It only works for single plane updates
1438 * - Async Pageflips are not supported yet
1439 * - Some hw might still scan out the old buffer until the next
1440 * vblank, however we let go of the fb references as soon as
1441 * we run this hook. For now drivers must implement their own workers
1442 * for deferring if needed, until a common solution is created.
1443 */
1444 void (*atomic_async_update)(struct drm_plane *plane,
1445 struct drm_atomic_state *state);
1446};
1447
1448/**
1449 * drm_plane_helper_add - sets the helper vtable for a plane
1450 * @plane: DRM plane
1451 * @funcs: helper vtable to set for @plane
1452 */
1453static inline void drm_plane_helper_add(struct drm_plane *plane,
1454 const struct drm_plane_helper_funcs *funcs)
1455{
1456 plane->helper_private = funcs;
1457}
1458
1459/**
1460 * struct drm_mode_config_helper_funcs - global modeset helper operations
1461 *
1462 * These helper functions are used by the atomic helpers.
1463 */
1464struct drm_mode_config_helper_funcs {
1465 /**
1466 * @atomic_commit_tail:
1467 *
1468 * This hook is used by the default atomic_commit() hook implemented in
1469 * drm_atomic_helper_commit() together with the nonblocking commit
1470 * helpers (see drm_atomic_helper_setup_commit() for a starting point)
1471 * to implement blocking and nonblocking commits easily. It is not used
1472 * by the atomic helpers
1473 *
1474 * This function is called when the new atomic state has already been
1475 * swapped into the various state pointers. The passed in state
1476 * therefore contains copies of the old/previous state. This hook should
1477 * commit the new state into hardware. Note that the helpers have
1478 * already waited for preceding atomic commits and fences, but drivers
1479 * can add more waiting calls at the start of their implementation, e.g.
1480 * to wait for driver-internal request for implicit syncing, before
1481 * starting to commit the update to the hardware.
1482 *
1483 * After the atomic update is committed to the hardware this hook needs
1484 * to call drm_atomic_helper_commit_hw_done(). Then wait for the update
1485 * to be executed by the hardware, for example using
1486 * drm_atomic_helper_wait_for_vblanks() or
1487 * drm_atomic_helper_wait_for_flip_done(), and then clean up the old
1488 * framebuffers using drm_atomic_helper_cleanup_planes().
1489 *
1490 * When disabling a CRTC this hook _must_ stall for the commit to
1491 * complete. Vblank waits don't work on disabled CRTC, hence the core
1492 * can't take care of this. And it also can't rely on the vblank event,
1493 * since that can be signalled already when the screen shows black,
1494 * which can happen much earlier than the last hardware access needed to
1495 * shut off the display pipeline completely.
1496 *
1497 * This hook is optional, the default implementation is
1498 * drm_atomic_helper_commit_tail().
1499 */
1500 void (*atomic_commit_tail)(struct drm_atomic_state *state);
1501
1502 /**
1503 * @atomic_commit_setup:
1504 *
1505 * This hook is used by the default atomic_commit() hook implemented in
1506 * drm_atomic_helper_commit() together with the nonblocking helpers (see
1507 * drm_atomic_helper_setup_commit()) to extend the DRM commit setup. It
1508 * is not used by the atomic helpers.
1509 *
1510 * This function is called at the end of
1511 * drm_atomic_helper_setup_commit(), so once the commit has been
1512 * properly setup across the generic DRM object states. It allows
1513 * drivers to do some additional commit tracking that isn't related to a
1514 * CRTC, plane or connector, tracked in a &drm_private_obj structure.
1515 *
1516 * Note that the documentation of &drm_private_obj has more details on
1517 * how one should implement this.
1518 *
1519 * This hook is optional.
1520 */
1521 int (*atomic_commit_setup)(struct drm_atomic_state *state);
1522};
1523
1524#endif
1525

source code of linux/include/drm/drm_modeset_helper_vtables.h