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_scanout_buffer;
52struct drm_writeback_connector;
53struct drm_writeback_job;
54
55enum mode_set_atomic {
56 LEAVE_ATOMIC_MODE_SET,
57 ENTER_ATOMIC_MODE_SET,
58};
59
60/**
61 * struct drm_crtc_helper_funcs - helper operations for CRTCs
62 *
63 * These hooks are used by the legacy CRTC helpers and the new atomic
64 * modesetting helpers.
65 */
66struct drm_crtc_helper_funcs {
67 /**
68 * @dpms:
69 *
70 * Callback to control power levels on the CRTC. If the mode passed in
71 * is unsupported, the provider must use the next lowest power level.
72 * This is used by the legacy CRTC helpers to implement DPMS
73 * functionality in drm_helper_connector_dpms().
74 *
75 * This callback is also used to disable a CRTC by calling it with
76 * DRM_MODE_DPMS_OFF if the @disable hook isn't used.
77 *
78 * This callback is used by the legacy CRTC helpers. Atomic helpers
79 * also support using this hook for enabling and disabling a CRTC to
80 * facilitate transitions to atomic, but it is deprecated. Instead
81 * @atomic_enable and @atomic_disable should be used.
82 */
83 void (*dpms)(struct drm_crtc *crtc, int mode);
84
85 /**
86 * @prepare:
87 *
88 * This callback should prepare the CRTC for a subsequent modeset, which
89 * in practice means the driver should disable the CRTC if it is
90 * running. Most drivers ended up implementing this by calling their
91 * @dpms hook with DRM_MODE_DPMS_OFF.
92 *
93 * This callback is used by the legacy CRTC helpers. Atomic helpers
94 * also support using this hook for disabling a CRTC to facilitate
95 * transitions to atomic, but it is deprecated. Instead @atomic_disable
96 * should be used.
97 */
98 void (*prepare)(struct drm_crtc *crtc);
99
100 /**
101 * @commit:
102 *
103 * This callback should commit the new mode on the CRTC after a modeset,
104 * which in practice means the driver should enable the CRTC. Most
105 * drivers ended up implementing this by calling their @dpms hook with
106 * DRM_MODE_DPMS_ON.
107 *
108 * This callback is used by the legacy CRTC helpers. Atomic helpers
109 * also support using this hook for enabling a CRTC to facilitate
110 * transitions to atomic, but it is deprecated. Instead @atomic_enable
111 * should be used.
112 */
113 void (*commit)(struct drm_crtc *crtc);
114
115 /**
116 * @mode_valid:
117 *
118 * This callback is used to check if a specific mode is valid in this
119 * crtc. This should be implemented if the crtc has some sort of
120 * restriction in the modes it can display. For example, a given crtc
121 * may be responsible to set a clock value. If the clock can not
122 * produce all the values for the available modes then this callback
123 * can be used to restrict the number of modes to only the ones that
124 * can be displayed.
125 *
126 * This hook is used by the probe helpers to filter the mode list in
127 * drm_helper_probe_single_connector_modes(), and it is used by the
128 * atomic helpers to validate modes supplied by userspace in
129 * drm_atomic_helper_check_modeset().
130 *
131 * This function is optional.
132 *
133 * NOTE:
134 *
135 * Since this function is both called from the check phase of an atomic
136 * commit, and the mode validation in the probe paths it is not allowed
137 * to look at anything else but the passed-in mode, and validate it
138 * against configuration-invariant hardware constraints. Any further
139 * limits which depend upon the configuration can only be checked in
140 * @mode_fixup or @atomic_check.
141 *
142 * RETURNS:
143 *
144 * drm_mode_status Enum
145 */
146 enum drm_mode_status (*mode_valid)(struct drm_crtc *crtc,
147 const struct drm_display_mode *mode);
148
149 /**
150 * @mode_fixup:
151 *
152 * This callback is used to validate a mode. The parameter mode is the
153 * display mode that userspace requested, adjusted_mode is the mode the
154 * encoders need to be fed with. Note that this is the inverse semantics
155 * of the meaning for the &drm_encoder and &drm_bridge_funcs.mode_fixup
156 * vfunc. If the CRTC cannot support the requested conversion from mode
157 * to adjusted_mode it should reject the modeset. See also
158 * &drm_crtc_state.adjusted_mode for more details.
159 *
160 * This function is used by both legacy CRTC helpers and atomic helpers.
161 * With atomic helpers it is optional.
162 *
163 * NOTE:
164 *
165 * This function is called in the check phase of atomic modesets, which
166 * can be aborted for any reason (including on userspace's request to
167 * just check whether a configuration would be possible). Atomic drivers
168 * MUST NOT touch any persistent state (hardware or software) or data
169 * structures except the passed in adjusted_mode parameter.
170 *
171 * This is in contrast to the legacy CRTC helpers where this was
172 * allowed.
173 *
174 * Atomic drivers which need to inspect and adjust more state should
175 * instead use the @atomic_check callback, but note that they're not
176 * perfectly equivalent: @mode_valid is called from
177 * drm_atomic_helper_check_modeset(), but @atomic_check is called from
178 * drm_atomic_helper_check_planes(), because originally it was meant for
179 * plane update checks only.
180 *
181 * Also beware that userspace can request its own custom modes, neither
182 * core nor helpers filter modes to the list of probe modes reported by
183 * the GETCONNECTOR IOCTL and stored in &drm_connector.modes. To ensure
184 * that modes are filtered consistently put any CRTC constraints and
185 * limits checks into @mode_valid.
186 *
187 * RETURNS:
188 *
189 * True if an acceptable configuration is possible, false if the modeset
190 * operation should be rejected.
191 */
192 bool (*mode_fixup)(struct drm_crtc *crtc,
193 const struct drm_display_mode *mode,
194 struct drm_display_mode *adjusted_mode);
195
196 /**
197 * @mode_set:
198 *
199 * This callback is used by the legacy CRTC helpers to set a new mode,
200 * position and framebuffer. Since it ties the primary plane to every
201 * mode change it is incompatible with universal plane support. And
202 * since it can't update other planes it's incompatible with atomic
203 * modeset support.
204 *
205 * This callback is only used by CRTC helpers and deprecated.
206 *
207 * RETURNS:
208 *
209 * 0 on success or a negative error code on failure.
210 */
211 int (*mode_set)(struct drm_crtc *crtc, struct drm_display_mode *mode,
212 struct drm_display_mode *adjusted_mode, int x, int y,
213 struct drm_framebuffer *old_fb);
214
215 /**
216 * @mode_set_nofb:
217 *
218 * This callback is used to update the display mode of a CRTC without
219 * changing anything of the primary plane configuration. This fits the
220 * requirement of atomic and hence is used by the atomic helpers.
221 *
222 * Note that the display pipe is completely off when this function is
223 * called. Atomic drivers which need hardware to be running before they
224 * program the new display mode (e.g. because they implement runtime PM)
225 * should not use this hook. This is because the helper library calls
226 * this hook only once per mode change and not every time the display
227 * pipeline is suspended using either DPMS or the new "ACTIVE" property.
228 * Which means register values set in this callback might get reset when
229 * the CRTC is suspended, but not restored. Such drivers should instead
230 * move all their CRTC setup into the @atomic_enable callback.
231 *
232 * This callback is optional.
233 */
234 void (*mode_set_nofb)(struct drm_crtc *crtc);
235
236 /**
237 * @mode_set_base:
238 *
239 * This callback is used by the legacy CRTC helpers to set a new
240 * framebuffer and scanout position. It is optional and used as an
241 * optimized fast-path instead of a full mode set operation with all the
242 * resulting flickering. If it is not present
243 * drm_crtc_helper_set_config() will fall back to a full modeset, using
244 * the @mode_set callback. Since it can't update other planes it's
245 * incompatible with atomic modeset support.
246 *
247 * This callback is only used by the CRTC helpers and deprecated.
248 *
249 * RETURNS:
250 *
251 * 0 on success or a negative error code on failure.
252 */
253 int (*mode_set_base)(struct drm_crtc *crtc, int x, int y,
254 struct drm_framebuffer *old_fb);
255
256 /**
257 * @mode_set_base_atomic:
258 *
259 * This callback is used by the fbdev helpers to set a new framebuffer
260 * and scanout without sleeping, i.e. from an atomic calling context. It
261 * is only used to implement kgdb support.
262 *
263 * This callback is optional and only needed for kgdb support in the fbdev
264 * helpers.
265 *
266 * RETURNS:
267 *
268 * 0 on success or a negative error code on failure.
269 */
270 int (*mode_set_base_atomic)(struct drm_crtc *crtc,
271 struct drm_framebuffer *fb, int x, int y,
272 enum mode_set_atomic);
273
274 /**
275 * @disable:
276 *
277 * This callback should be used to disable the CRTC. With the atomic
278 * drivers it is called after all encoders connected to this CRTC have
279 * been shut off already using their own
280 * &drm_encoder_helper_funcs.disable hook. If that sequence is too
281 * simple drivers can just add their own hooks and call it from this
282 * CRTC callback here by looping over all encoders connected to it using
283 * for_each_encoder_on_crtc().
284 *
285 * This hook is used both by legacy CRTC helpers and atomic helpers.
286 * Atomic drivers don't need to implement it if there's no need to
287 * disable anything at the CRTC level. To ensure that runtime PM
288 * handling (using either DPMS or the new "ACTIVE" property) works
289 * @disable must be the inverse of @atomic_enable for atomic drivers.
290 * Atomic drivers should consider to use @atomic_disable instead of
291 * this one.
292 *
293 * NOTE:
294 *
295 * With legacy CRTC helpers there's a big semantic difference between
296 * @disable and other hooks (like @prepare or @dpms) used to shut down a
297 * CRTC: @disable is only called when also logically disabling the
298 * display pipeline and needs to release any resources acquired in
299 * @mode_set (like shared PLLs, or again release pinned framebuffers).
300 *
301 * Therefore @disable must be the inverse of @mode_set plus @commit for
302 * drivers still using legacy CRTC helpers, which is different from the
303 * rules under atomic.
304 */
305 void (*disable)(struct drm_crtc *crtc);
306
307 /**
308 * @atomic_check:
309 *
310 * Drivers should check plane-update related CRTC constraints in this
311 * hook. They can also check mode related limitations but need to be
312 * aware of the calling order, since this hook is used by
313 * drm_atomic_helper_check_planes() whereas the preparations needed to
314 * check output routing and the display mode is done in
315 * drm_atomic_helper_check_modeset(). Therefore drivers that want to
316 * check output routing and display mode constraints in this callback
317 * must ensure that drm_atomic_helper_check_modeset() has been called
318 * beforehand. This is calling order used by the default helper
319 * implementation in drm_atomic_helper_check().
320 *
321 * When using drm_atomic_helper_check_planes() this hook is called
322 * after the &drm_plane_helper_funcs.atomic_check hook for planes, which
323 * allows drivers to assign shared resources requested by planes in this
324 * callback here. For more complicated dependencies the driver can call
325 * the provided check helpers multiple times until the computed state
326 * has a final configuration and everything has been checked.
327 *
328 * This function is also allowed to inspect any other object's state and
329 * can add more state objects to the atomic commit if needed. Care must
330 * be taken though to ensure that state check and compute functions for
331 * these added states are all called, and derived state in other objects
332 * all updated. Again the recommendation is to just call check helpers
333 * until a maximal configuration is reached.
334 *
335 * This callback is used by the atomic modeset helpers, but it is
336 * optional.
337 *
338 * NOTE:
339 *
340 * This function is called in the check phase of an atomic update. The
341 * driver is not allowed to change anything outside of the free-standing
342 * state object passed-in.
343 *
344 * Also beware that userspace can request its own custom modes, neither
345 * core nor helpers filter modes to the list of probe modes reported by
346 * the GETCONNECTOR IOCTL and stored in &drm_connector.modes. To ensure
347 * that modes are filtered consistently put any CRTC constraints and
348 * limits checks into @mode_valid.
349 *
350 * RETURNS:
351 *
352 * 0 on success, -EINVAL if the state or the transition can't be
353 * supported, -ENOMEM on memory allocation failure and -EDEADLK if an
354 * attempt to obtain another state object ran into a &drm_modeset_lock
355 * deadlock.
356 */
357 int (*atomic_check)(struct drm_crtc *crtc,
358 struct drm_atomic_state *state);
359
360 /**
361 * @atomic_begin:
362 *
363 * Drivers should prepare for an atomic update of multiple planes on
364 * a CRTC in this hook. Depending upon hardware this might be vblank
365 * evasion, blocking updates by setting bits or doing preparatory work
366 * for e.g. manual update display.
367 *
368 * This hook is called before any plane commit functions are called.
369 *
370 * Note that the power state of the display pipe when this function is
371 * called depends upon the exact helpers and calling sequence the driver
372 * has picked. See drm_atomic_helper_commit_planes() for a discussion of
373 * the tradeoffs and variants of plane commit helpers.
374 *
375 * This callback is used by the atomic modeset helpers, but it is
376 * optional.
377 */
378 void (*atomic_begin)(struct drm_crtc *crtc,
379 struct drm_atomic_state *state);
380 /**
381 * @atomic_flush:
382 *
383 * Drivers should finalize an atomic update of multiple planes on
384 * a CRTC in this hook. Depending upon hardware this might include
385 * checking that vblank evasion was successful, unblocking updates by
386 * setting bits or setting the GO bit to flush out all updates.
387 *
388 * Simple hardware or hardware with special requirements can commit and
389 * flush out all updates for all planes from this hook and forgo all the
390 * other commit hooks for plane updates.
391 *
392 * This hook is called after any plane commit functions are called.
393 *
394 * Note that the power state of the display pipe when this function is
395 * called depends upon the exact helpers and calling sequence the driver
396 * has picked. See drm_atomic_helper_commit_planes() for a discussion of
397 * the tradeoffs and variants of plane commit helpers.
398 *
399 * This callback is used by the atomic modeset helpers, but it is
400 * optional.
401 */
402 void (*atomic_flush)(struct drm_crtc *crtc,
403 struct drm_atomic_state *state);
404
405 /**
406 * @atomic_enable:
407 *
408 * This callback should be used to enable the CRTC. With the atomic
409 * drivers it is called before all encoders connected to this CRTC are
410 * enabled through the encoder's own &drm_encoder_helper_funcs.enable
411 * hook. If that sequence is too simple drivers can just add their own
412 * hooks and call it from this CRTC callback here by looping over all
413 * encoders connected to it using for_each_encoder_on_crtc().
414 *
415 * This hook is used only by atomic helpers, for symmetry with
416 * @atomic_disable. Atomic drivers don't need to implement it if there's
417 * no need to enable anything at the CRTC level. To ensure that runtime
418 * PM handling (using either DPMS or the new "ACTIVE" property) works
419 * @atomic_enable must be the inverse of @atomic_disable for atomic
420 * drivers.
421 *
422 * This function is optional.
423 */
424 void (*atomic_enable)(struct drm_crtc *crtc,
425 struct drm_atomic_state *state);
426
427 /**
428 * @atomic_disable:
429 *
430 * This callback should be used to disable the CRTC. With the atomic
431 * drivers it is called after all encoders connected to this CRTC have
432 * been shut off already using their own
433 * &drm_encoder_helper_funcs.disable hook. If that sequence is too
434 * simple drivers can just add their own hooks and call it from this
435 * CRTC callback here by looping over all encoders connected to it using
436 * for_each_encoder_on_crtc().
437 *
438 * This hook is used only by atomic helpers. Atomic drivers don't
439 * need to implement it if there's no need to disable anything at the
440 * CRTC level.
441 *
442 * This function is optional.
443 */
444 void (*atomic_disable)(struct drm_crtc *crtc,
445 struct drm_atomic_state *state);
446
447 /**
448 * @get_scanout_position:
449 *
450 * Called by vblank timestamping code.
451 *
452 * Returns the current display scanout position from a CRTC and an
453 * optional accurate ktime_get() timestamp of when the position was
454 * measured. Note that this is a helper callback which is only used
455 * if a driver uses drm_crtc_vblank_helper_get_vblank_timestamp()
456 * for the @drm_crtc_funcs.get_vblank_timestamp callback.
457 *
458 * Parameters:
459 *
460 * crtc:
461 * The CRTC.
462 * in_vblank_irq:
463 * True when called from drm_crtc_handle_vblank(). Some drivers
464 * need to apply some workarounds for gpu-specific vblank irq
465 * quirks if the flag is set.
466 * vpos:
467 * Target location for current vertical scanout position.
468 * hpos:
469 * Target location for current horizontal scanout position.
470 * stime:
471 * Target location for timestamp taken immediately before
472 * scanout position query. Can be NULL to skip timestamp.
473 * etime:
474 * Target location for timestamp taken immediately after
475 * scanout position query. Can be NULL to skip timestamp.
476 * mode:
477 * Current display timings.
478 *
479 * Returns vpos as a positive number while in active scanout area.
480 * Returns vpos as a negative number inside vblank, counting the number
481 * of scanlines to go until end of vblank, e.g., -1 means "one scanline
482 * until start of active scanout / end of vblank."
483 *
484 * Returns:
485 *
486 * True on success, false if a reliable scanout position counter could
487 * not be read out.
488 */
489 bool (*get_scanout_position)(struct drm_crtc *crtc,
490 bool in_vblank_irq, int *vpos, int *hpos,
491 ktime_t *stime, ktime_t *etime,
492 const struct drm_display_mode *mode);
493
494 /**
495 * @handle_vblank_timeout: Handles timeouts of the vblank timer.
496 *
497 * Called by CRTC's the vblank timer on each timeout. Semantics is
498 * equivalient to drm_crtc_handle_vblank(). Implementations should
499 * invoke drm_crtc_handle_vblank() as part of processing the timeout.
500 *
501 * This callback is optional. If unset, the vblank timer invokes
502 * drm_crtc_handle_vblank() directly.
503 */
504 bool (*handle_vblank_timeout)(struct drm_crtc *crtc);
505};
506
507/**
508 * drm_crtc_helper_add - sets the helper vtable for a crtc
509 * @crtc: DRM CRTC
510 * @funcs: helper vtable to set for @crtc
511 */
512static inline void drm_crtc_helper_add(struct drm_crtc *crtc,
513 const struct drm_crtc_helper_funcs *funcs)
514{
515 crtc->helper_private = funcs;
516}
517
518/**
519 * struct drm_encoder_helper_funcs - helper operations for encoders
520 *
521 * These hooks are used by the legacy CRTC helpers and the new atomic
522 * modesetting helpers.
523 */
524struct drm_encoder_helper_funcs {
525 /**
526 * @dpms:
527 *
528 * Callback to control power levels on the encoder. If the mode passed in
529 * is unsupported, the provider must use the next lowest power level.
530 * This is used by the legacy encoder helpers to implement DPMS
531 * functionality in drm_helper_connector_dpms().
532 *
533 * This callback is also used to disable an encoder by calling it with
534 * DRM_MODE_DPMS_OFF if the @disable hook isn't used.
535 *
536 * This callback is used by the legacy CRTC helpers. Atomic helpers
537 * also support using this hook for enabling and disabling an encoder to
538 * facilitate transitions to atomic, but it is deprecated. Instead
539 * @enable and @disable should be used.
540 */
541 void (*dpms)(struct drm_encoder *encoder, int mode);
542
543 /**
544 * @mode_valid:
545 *
546 * This callback is used to check if a specific mode is valid in this
547 * encoder. This should be implemented if the encoder has some sort
548 * of restriction in the modes it can display. For example, a given
549 * encoder may be responsible to set a clock value. If the clock can
550 * not produce all the values for the available modes then this callback
551 * can be used to restrict the number of modes to only the ones that
552 * can be displayed.
553 *
554 * This hook is used by the probe helpers to filter the mode list in
555 * drm_helper_probe_single_connector_modes(), and it is used by the
556 * atomic helpers to validate modes supplied by userspace in
557 * drm_atomic_helper_check_modeset().
558 *
559 * This function is optional.
560 *
561 * NOTE:
562 *
563 * Since this function is both called from the check phase of an atomic
564 * commit, and the mode validation in the probe paths it is not allowed
565 * to look at anything else but the passed-in mode, and validate it
566 * against configuration-invariant hardware constraints. Any further
567 * limits which depend upon the configuration can only be checked in
568 * @mode_fixup or @atomic_check.
569 *
570 * RETURNS:
571 *
572 * drm_mode_status Enum
573 */
574 enum drm_mode_status (*mode_valid)(struct drm_encoder *crtc,
575 const struct drm_display_mode *mode);
576
577 /**
578 * @mode_fixup:
579 *
580 * This callback is used to validate and adjust a mode. The parameter
581 * mode is the display mode that should be fed to the next element in
582 * the display chain, either the final &drm_connector or a &drm_bridge.
583 * The parameter adjusted_mode is the input mode the encoder requires. It
584 * can be modified by this callback and does not need to match mode. See
585 * also &drm_crtc_state.adjusted_mode for more details.
586 *
587 * This function is used by both legacy CRTC helpers and atomic helpers.
588 * This hook is optional.
589 *
590 * NOTE:
591 *
592 * This function is called in the check phase of atomic modesets, which
593 * can be aborted for any reason (including on userspace's request to
594 * just check whether a configuration would be possible). Atomic drivers
595 * MUST NOT touch any persistent state (hardware or software) or data
596 * structures except the passed in adjusted_mode parameter.
597 *
598 * This is in contrast to the legacy CRTC helpers where this was
599 * allowed.
600 *
601 * Atomic drivers which need to inspect and adjust more state should
602 * instead use the @atomic_check callback. If @atomic_check is used,
603 * this hook isn't called since @atomic_check allows a strict superset
604 * of the functionality of @mode_fixup.
605 *
606 * Also beware that userspace can request its own custom modes, neither
607 * core nor helpers filter modes to the list of probe modes reported by
608 * the GETCONNECTOR IOCTL and stored in &drm_connector.modes. To ensure
609 * that modes are filtered consistently put any encoder constraints and
610 * limits checks into @mode_valid.
611 *
612 * RETURNS:
613 *
614 * True if an acceptable configuration is possible, false if the modeset
615 * operation should be rejected.
616 */
617 bool (*mode_fixup)(struct drm_encoder *encoder,
618 const struct drm_display_mode *mode,
619 struct drm_display_mode *adjusted_mode);
620
621 /**
622 * @prepare:
623 *
624 * This callback should prepare the encoder for a subsequent modeset,
625 * which in practice means the driver should disable the encoder if it
626 * is running. Most drivers ended up implementing this by calling their
627 * @dpms hook with DRM_MODE_DPMS_OFF.
628 *
629 * This callback is used by the legacy CRTC helpers. Atomic helpers
630 * also support using this hook for disabling an encoder to facilitate
631 * transitions to atomic, but it is deprecated. Instead @disable should
632 * be used.
633 */
634 void (*prepare)(struct drm_encoder *encoder);
635
636 /**
637 * @commit:
638 *
639 * This callback should commit the new mode on the encoder after a modeset,
640 * which in practice means the driver should enable the encoder. Most
641 * drivers ended up implementing this by calling their @dpms hook with
642 * DRM_MODE_DPMS_ON.
643 *
644 * This callback is used by the legacy CRTC helpers. Atomic helpers
645 * also support using this hook for enabling an encoder to facilitate
646 * transitions to atomic, but it is deprecated. Instead @enable should
647 * be used.
648 */
649 void (*commit)(struct drm_encoder *encoder);
650
651 /**
652 * @mode_set:
653 *
654 * This callback is used to update the display mode of an encoder.
655 *
656 * Note that the display pipe is completely off when this function is
657 * called. Drivers which need hardware to be running before they program
658 * the new display mode (because they implement runtime PM) should not
659 * use this hook, because the helper library calls it only once and not
660 * every time the display pipeline is suspend using either DPMS or the
661 * new "ACTIVE" property. Such drivers should instead move all their
662 * encoder setup into the @enable callback.
663 *
664 * This callback is used both by the legacy CRTC helpers and the atomic
665 * modeset helpers. It is optional in the atomic helpers.
666 *
667 * NOTE:
668 *
669 * If the driver uses the atomic modeset helpers and needs to inspect
670 * the connector state or connector display info during mode setting,
671 * @atomic_mode_set can be used instead.
672 */
673 void (*mode_set)(struct drm_encoder *encoder,
674 struct drm_display_mode *mode,
675 struct drm_display_mode *adjusted_mode);
676
677 /**
678 * @atomic_mode_set:
679 *
680 * This callback is used to update the display mode of an encoder.
681 *
682 * Note that the display pipe is completely off when this function is
683 * called. Drivers which need hardware to be running before they program
684 * the new display mode (because they implement runtime PM) should not
685 * use this hook, because the helper library calls it only once and not
686 * every time the display pipeline is suspended using either DPMS or the
687 * new "ACTIVE" property. Such drivers should instead move all their
688 * encoder setup into the @enable callback.
689 *
690 * This callback is used by the atomic modeset helpers in place of the
691 * @mode_set callback, if set by the driver. It is optional and should
692 * be used instead of @mode_set if the driver needs to inspect the
693 * connector state or display info, since there is no direct way to
694 * go from the encoder to the current connector.
695 */
696 void (*atomic_mode_set)(struct drm_encoder *encoder,
697 struct drm_crtc_state *crtc_state,
698 struct drm_connector_state *conn_state);
699
700 /**
701 * @detect:
702 *
703 * This callback can be used by drivers who want to do detection on the
704 * encoder object instead of in connector functions.
705 *
706 * It is not used by any helper and therefore has purely driver-specific
707 * semantics. New drivers shouldn't use this and instead just implement
708 * their own private callbacks.
709 *
710 * FIXME:
711 *
712 * This should just be converted into a pile of driver vfuncs.
713 * Currently radeon, amdgpu and nouveau are using it.
714 */
715 enum drm_connector_status (*detect)(struct drm_encoder *encoder,
716 struct drm_connector *connector);
717
718 /**
719 * @atomic_disable:
720 *
721 * This callback should be used to disable the encoder. With the atomic
722 * drivers it is called before this encoder's CRTC has been shut off
723 * using their own &drm_crtc_helper_funcs.atomic_disable hook. If that
724 * sequence is too simple drivers can just add their own driver private
725 * encoder hooks and call them from CRTC's callback by looping over all
726 * encoders connected to it using for_each_encoder_on_crtc().
727 *
728 * This callback is a variant of @disable that provides the atomic state
729 * to the driver. If @atomic_disable is implemented, @disable is not
730 * called by the helpers.
731 *
732 * This hook is only used by atomic helpers. Atomic drivers don't need
733 * to implement it if there's no need to disable anything at the encoder
734 * level. To ensure that runtime PM handling (using either DPMS or the
735 * new "ACTIVE" property) works @atomic_disable must be the inverse of
736 * @atomic_enable.
737 */
738 void (*atomic_disable)(struct drm_encoder *encoder,
739 struct drm_atomic_state *state);
740
741 /**
742 * @atomic_enable:
743 *
744 * This callback should be used to enable the encoder. It is called
745 * after this encoder's CRTC has been enabled using their own
746 * &drm_crtc_helper_funcs.atomic_enable hook. If that sequence is
747 * too simple drivers can just add their own driver private encoder
748 * hooks and call them from CRTC's callback by looping over all encoders
749 * connected to it using for_each_encoder_on_crtc().
750 *
751 * This callback is a variant of @enable that provides the atomic state
752 * to the driver. If @atomic_enable is implemented, @enable is not
753 * called by the helpers.
754 *
755 * This hook is only used by atomic helpers, it is the opposite of
756 * @atomic_disable. Atomic drivers don't need to implement it if there's
757 * no need to enable anything at the encoder level. To ensure that
758 * runtime PM handling works @atomic_enable must be the inverse of
759 * @atomic_disable.
760 */
761 void (*atomic_enable)(struct drm_encoder *encoder,
762 struct drm_atomic_state *state);
763
764 /**
765 * @disable:
766 *
767 * This callback should be used to disable the encoder. With the atomic
768 * drivers it is called before this encoder's CRTC has been shut off
769 * using their own &drm_crtc_helper_funcs.disable hook. If that
770 * sequence is too simple drivers can just add their own driver private
771 * encoder hooks and call them from CRTC's callback by looping over all
772 * encoders connected to it using for_each_encoder_on_crtc().
773 *
774 * This hook is used both by legacy CRTC helpers and atomic helpers.
775 * Atomic drivers don't need to implement it if there's no need to
776 * disable anything at the encoder level. To ensure that runtime PM
777 * handling (using either DPMS or the new "ACTIVE" property) works
778 * @disable must be the inverse of @enable for atomic drivers.
779 *
780 * For atomic drivers also consider @atomic_disable and save yourself
781 * from having to read the NOTE below!
782 *
783 * NOTE:
784 *
785 * With legacy CRTC helpers there's a big semantic difference between
786 * @disable and other hooks (like @prepare or @dpms) used to shut down a
787 * encoder: @disable is only called when also logically disabling the
788 * display pipeline and needs to release any resources acquired in
789 * @mode_set (like shared PLLs, or again release pinned framebuffers).
790 *
791 * Therefore @disable must be the inverse of @mode_set plus @commit for
792 * drivers still using legacy CRTC helpers, which is different from the
793 * rules under atomic.
794 */
795 void (*disable)(struct drm_encoder *encoder);
796
797 /**
798 * @enable:
799 *
800 * This callback should be used to enable the encoder. With the atomic
801 * drivers it is called after this encoder's CRTC has been enabled using
802 * their own &drm_crtc_helper_funcs.enable hook. If that sequence is
803 * too simple drivers can just add their own driver private encoder
804 * hooks and call them from CRTC's callback by looping over all encoders
805 * connected to it using for_each_encoder_on_crtc().
806 *
807 * This hook is only used by atomic helpers, it is the opposite of
808 * @disable. Atomic drivers don't need to implement it if there's no
809 * need to enable anything at the encoder level. To ensure that
810 * runtime PM handling (using either DPMS or the new "ACTIVE" property)
811 * works @enable must be the inverse of @disable for atomic drivers.
812 */
813 void (*enable)(struct drm_encoder *encoder);
814
815 /**
816 * @atomic_check:
817 *
818 * This callback is used to validate encoder state for atomic drivers.
819 * Since the encoder is the object connecting the CRTC and connector it
820 * gets passed both states, to be able to validate interactions and
821 * update the CRTC to match what the encoder needs for the requested
822 * connector.
823 *
824 * Since this provides a strict superset of the functionality of
825 * @mode_fixup (the requested and adjusted modes are both available
826 * through the passed in &struct drm_crtc_state) @mode_fixup is not
827 * called when @atomic_check is implemented.
828 *
829 * This function is used by the atomic helpers, but it is optional.
830 *
831 * NOTE:
832 *
833 * This function is called in the check phase of an atomic update. The
834 * driver is not allowed to change anything outside of the free-standing
835 * state objects passed-in or assembled in the overall &drm_atomic_state
836 * update tracking structure.
837 *
838 * Also beware that userspace can request its own custom modes, neither
839 * core nor helpers filter modes to the list of probe modes reported by
840 * the GETCONNECTOR IOCTL and stored in &drm_connector.modes. To ensure
841 * that modes are filtered consistently put any encoder constraints and
842 * limits checks into @mode_valid.
843 *
844 * RETURNS:
845 *
846 * 0 on success, -EINVAL if the state or the transition can't be
847 * supported, -ENOMEM on memory allocation failure and -EDEADLK if an
848 * attempt to obtain another state object ran into a &drm_modeset_lock
849 * deadlock.
850 */
851 int (*atomic_check)(struct drm_encoder *encoder,
852 struct drm_crtc_state *crtc_state,
853 struct drm_connector_state *conn_state);
854};
855
856/**
857 * drm_encoder_helper_add - sets the helper vtable for an encoder
858 * @encoder: DRM encoder
859 * @funcs: helper vtable to set for @encoder
860 */
861static inline void drm_encoder_helper_add(struct drm_encoder *encoder,
862 const struct drm_encoder_helper_funcs *funcs)
863{
864 encoder->helper_private = funcs;
865}
866
867/**
868 * struct drm_connector_helper_funcs - helper operations for connectors
869 *
870 * These functions are used by the atomic and legacy modeset helpers and by the
871 * probe helpers.
872 */
873struct drm_connector_helper_funcs {
874 /**
875 * @get_modes:
876 *
877 * This function should fill in all modes currently valid for the sink
878 * into the &drm_connector.probed_modes list. It should also update the
879 * EDID property by calling drm_connector_update_edid_property().
880 *
881 * The usual way to implement this is to cache the EDID retrieved in the
882 * probe callback somewhere in the driver-private connector structure.
883 * In this function drivers then parse the modes in the EDID and add
884 * them by calling drm_add_edid_modes(). But connectors that drive a
885 * fixed panel can also manually add specific modes using
886 * drm_mode_probed_add(). Drivers which manually add modes should also
887 * make sure that the &drm_connector.display_info,
888 * &drm_connector.width_mm and &drm_connector.height_mm fields are
889 * filled in.
890 *
891 * Note that the caller function will automatically add standard VESA
892 * DMT modes up to 1024x768 if the .get_modes() helper operation returns
893 * no mode and if the connector status is connector_status_connected or
894 * connector_status_unknown. There is no need to call
895 * drm_add_modes_noedid() manually in that case.
896 *
897 * Virtual drivers that just want some standard VESA mode with a given
898 * resolution can call drm_add_modes_noedid(), and mark the preferred
899 * one using drm_set_preferred_mode().
900 *
901 * This function is only called after the @detect hook has indicated
902 * that a sink is connected and when the EDID isn't overridden through
903 * sysfs or the kernel commandline.
904 *
905 * This callback is used by the probe helpers in e.g.
906 * drm_helper_probe_single_connector_modes().
907 *
908 * To avoid races with concurrent connector state updates, the helper
909 * libraries always call this with the &drm_mode_config.connection_mutex
910 * held. Because of this it's safe to inspect &drm_connector->state.
911 *
912 * RETURNS:
913 *
914 * The number of modes added by calling drm_mode_probed_add(). Return 0
915 * on failures (no modes) instead of negative error codes.
916 */
917 int (*get_modes)(struct drm_connector *connector);
918
919 /**
920 * @detect_ctx:
921 *
922 * Check to see if anything is attached to the connector. The parameter
923 * force is set to false whilst polling, true when checking the
924 * connector due to a user request. force can be used by the driver to
925 * avoid expensive, destructive operations during automated probing.
926 *
927 * This callback is optional, if not implemented the connector will be
928 * considered as always being attached.
929 *
930 * This is the atomic version of &drm_connector_funcs.detect.
931 *
932 * To avoid races against concurrent connector state updates, the
933 * helper libraries always call this with ctx set to a valid context,
934 * and &drm_mode_config.connection_mutex will always be locked with
935 * the ctx parameter set to this ctx. This allows taking additional
936 * locks as required.
937 *
938 * RETURNS:
939 *
940 * &drm_connector_status indicating the connector's status,
941 * or the error code returned by drm_modeset_lock(), -EDEADLK.
942 */
943 int (*detect_ctx)(struct drm_connector *connector,
944 struct drm_modeset_acquire_ctx *ctx,
945 bool force);
946
947 /**
948 * @mode_valid:
949 *
950 * Callback to validate a mode for a connector, irrespective of the
951 * specific display configuration.
952 *
953 * This callback is used by the probe helpers to filter the mode list
954 * (which is usually derived from the EDID data block from the sink).
955 * See e.g. drm_helper_probe_single_connector_modes().
956 *
957 * This function is optional.
958 *
959 * NOTE:
960 *
961 * This only filters the mode list supplied to userspace in the
962 * GETCONNECTOR IOCTL. Compared to &drm_encoder_helper_funcs.mode_valid,
963 * &drm_crtc_helper_funcs.mode_valid and &drm_bridge_funcs.mode_valid,
964 * which are also called by the atomic helpers from
965 * drm_atomic_helper_check_modeset(). This allows userspace to force and
966 * ignore sink constraint (like the pixel clock limits in the screen's
967 * EDID), which is useful for e.g. testing, or working around a broken
968 * EDID. Any source hardware constraint (which always need to be
969 * enforced) therefore should be checked in one of the above callbacks,
970 * and not this one here.
971 *
972 * To avoid races with concurrent connector state updates, the helper
973 * libraries always call this with the &drm_mode_config.connection_mutex
974 * held. Because of this it's safe to inspect &drm_connector->state.
975 *
976 * RETURNS:
977 *
978 * Either &drm_mode_status.MODE_OK or one of the failure reasons in &enum
979 * drm_mode_status.
980 */
981 enum drm_mode_status (*mode_valid)(struct drm_connector *connector,
982 const struct drm_display_mode *mode);
983
984 /**
985 * @mode_valid_ctx:
986 *
987 * Callback to validate a mode for a connector, irrespective of the
988 * specific display configuration.
989 *
990 * This callback is used by the probe helpers to filter the mode list
991 * (which is usually derived from the EDID data block from the sink).
992 * See e.g. drm_helper_probe_single_connector_modes().
993 *
994 * This function is optional, and is the atomic version of
995 * &drm_connector_helper_funcs.mode_valid.
996 *
997 * To allow for accessing the atomic state of modesetting objects, the
998 * helper libraries always call this with ctx set to a valid context,
999 * and &drm_mode_config.connection_mutex will always be locked with
1000 * the ctx parameter set to @ctx. This allows for taking additional
1001 * locks as required.
1002 *
1003 * Even though additional locks may be acquired, this callback is
1004 * still expected not to take any constraints into account which would
1005 * be influenced by the currently set display state - such constraints
1006 * should be handled in the driver's atomic check. For example, if a
1007 * connector shares display bandwidth with other connectors then it
1008 * would be ok to validate the minimum bandwidth requirement of a mode
1009 * against the maximum possible bandwidth of the connector. But it
1010 * wouldn't be ok to take the current bandwidth usage of other
1011 * connectors into account, as this would change depending on the
1012 * display state.
1013 *
1014 * Returns:
1015 * 0 if &drm_connector_helper_funcs.mode_valid_ctx succeeded and wrote
1016 * the &enum drm_mode_status value to @status, or a negative error
1017 * code otherwise.
1018 *
1019 */
1020 int (*mode_valid_ctx)(struct drm_connector *connector,
1021 const struct drm_display_mode *mode,
1022 struct drm_modeset_acquire_ctx *ctx,
1023 enum drm_mode_status *status);
1024
1025 /**
1026 * @best_encoder:
1027 *
1028 * This function should select the best encoder for the given connector.
1029 *
1030 * This function is used by both the atomic helpers (in the
1031 * drm_atomic_helper_check_modeset() function) and in the legacy CRTC
1032 * helpers.
1033 *
1034 * NOTE:
1035 *
1036 * In atomic drivers this function is called in the check phase of an
1037 * atomic update. The driver is not allowed to change or inspect
1038 * anything outside of arguments passed-in. Atomic drivers which need to
1039 * inspect dynamic configuration state should instead use
1040 * @atomic_best_encoder.
1041 *
1042 * You can leave this function to NULL if the connector is only
1043 * attached to a single encoder. In this case, the core will call
1044 * drm_connector_get_single_encoder() for you.
1045 *
1046 * RETURNS:
1047 *
1048 * Encoder that should be used for the given connector and connector
1049 * state, or NULL if no suitable encoder exists. Note that the helpers
1050 * will ensure that encoders aren't used twice, drivers should not check
1051 * for this.
1052 */
1053 struct drm_encoder *(*best_encoder)(struct drm_connector *connector);
1054
1055 /**
1056 * @atomic_best_encoder:
1057 *
1058 * This is the atomic version of @best_encoder for atomic drivers which
1059 * need to select the best encoder depending upon the desired
1060 * configuration and can't select it statically.
1061 *
1062 * This function is used by drm_atomic_helper_check_modeset().
1063 * If it is not implemented, the core will fallback to @best_encoder
1064 * (or drm_connector_get_single_encoder() if @best_encoder is NULL).
1065 *
1066 * NOTE:
1067 *
1068 * This function is called in the check phase of an atomic update. The
1069 * driver is not allowed to change anything outside of the
1070 * &drm_atomic_state update tracking structure passed in.
1071 *
1072 * RETURNS:
1073 *
1074 * Encoder that should be used for the given connector and connector
1075 * state, or NULL if no suitable encoder exists. Note that the helpers
1076 * will ensure that encoders aren't used twice, drivers should not check
1077 * for this.
1078 */
1079 struct drm_encoder *(*atomic_best_encoder)(struct drm_connector *connector,
1080 struct drm_atomic_state *state);
1081
1082 /**
1083 * @atomic_check:
1084 *
1085 * This hook is used to validate connector state. This function is
1086 * called from &drm_atomic_helper_check_modeset, and is called when
1087 * a connector property is set, or a modeset on the crtc is forced.
1088 *
1089 * Because &drm_atomic_helper_check_modeset may be called multiple times,
1090 * this function should handle being called multiple times as well.
1091 *
1092 * This function is also allowed to inspect any other object's state and
1093 * can add more state objects to the atomic commit if needed. Care must
1094 * be taken though to ensure that state check and compute functions for
1095 * these added states are all called, and derived state in other objects
1096 * all updated. Again the recommendation is to just call check helpers
1097 * until a maximal configuration is reached.
1098 *
1099 * NOTE:
1100 *
1101 * This function is called in the check phase of an atomic update. The
1102 * driver is not allowed to change anything outside of the free-standing
1103 * state objects passed-in or assembled in the overall &drm_atomic_state
1104 * update tracking structure.
1105 *
1106 * RETURNS:
1107 *
1108 * 0 on success, -EINVAL if the state or the transition can't be
1109 * supported, -ENOMEM on memory allocation failure and -EDEADLK if an
1110 * attempt to obtain another state object ran into a &drm_modeset_lock
1111 * deadlock.
1112 */
1113 int (*atomic_check)(struct drm_connector *connector,
1114 struct drm_atomic_state *state);
1115
1116 /**
1117 * @atomic_commit:
1118 *
1119 * This hook is to be used by drivers implementing writeback connectors
1120 * that need a point when to commit the writeback job to the hardware.
1121 * The writeback_job to commit is available in the new connector state,
1122 * in &drm_connector_state.writeback_job.
1123 *
1124 * This hook is optional.
1125 *
1126 * This callback is used by the atomic modeset helpers.
1127 */
1128 void (*atomic_commit)(struct drm_connector *connector,
1129 struct drm_atomic_state *state);
1130
1131 /**
1132 * @prepare_writeback_job:
1133 *
1134 * As writeback jobs contain a framebuffer, drivers may need to
1135 * prepare and clean them up the same way they can prepare and
1136 * clean up framebuffers for planes. This optional connector operation
1137 * is used to support the preparation of writeback jobs. The job
1138 * prepare operation is called from drm_atomic_helper_prepare_planes()
1139 * for struct &drm_writeback_connector connectors only.
1140 *
1141 * This operation is optional.
1142 *
1143 * This callback is used by the atomic modeset helpers.
1144 */
1145 int (*prepare_writeback_job)(struct drm_writeback_connector *connector,
1146 struct drm_writeback_job *job);
1147 /**
1148 * @cleanup_writeback_job:
1149 *
1150 * This optional connector operation is used to support the
1151 * cleanup of writeback jobs. The job cleanup operation is called
1152 * from the existing drm_writeback_cleanup_job() function, invoked
1153 * both when destroying the job as part of an aborted commit, or when
1154 * the job completes.
1155 *
1156 * This operation is optional.
1157 *
1158 * This callback is used by the atomic modeset helpers.
1159 */
1160 void (*cleanup_writeback_job)(struct drm_writeback_connector *connector,
1161 struct drm_writeback_job *job);
1162
1163 /**
1164 * @enable_hpd:
1165 *
1166 * Enable hot-plug detection for the connector.
1167 *
1168 * This operation is optional.
1169 *
1170 * This callback is used by the drm_kms_helper_poll_enable() helpers.
1171 *
1172 * This operation does not need to perform any hpd state tracking as
1173 * the DRM core handles that maintenance and ensures the calls to enable
1174 * and disable hpd are balanced.
1175 *
1176 */
1177 void (*enable_hpd)(struct drm_connector *connector);
1178
1179 /**
1180 * @disable_hpd:
1181 *
1182 * Disable hot-plug detection for the connector.
1183 *
1184 * This operation is optional.
1185 *
1186 * This callback is used by the drm_kms_helper_poll_disable() helpers.
1187 *
1188 * This operation does not need to perform any hpd state tracking as
1189 * the DRM core handles that maintenance and ensures the calls to enable
1190 * and disable hpd are balanced.
1191 *
1192 */
1193 void (*disable_hpd)(struct drm_connector *connector);
1194};
1195
1196/**
1197 * drm_connector_helper_add - sets the helper vtable for a connector
1198 * @connector: DRM connector
1199 * @funcs: helper vtable to set for @connector
1200 */
1201static inline void drm_connector_helper_add(struct drm_connector *connector,
1202 const struct drm_connector_helper_funcs *funcs)
1203{
1204 connector->helper_private = funcs;
1205}
1206
1207/**
1208 * struct drm_plane_helper_funcs - helper operations for planes
1209 *
1210 * These functions are used by the atomic helpers.
1211 */
1212struct drm_plane_helper_funcs {
1213 /**
1214 * @prepare_fb:
1215 *
1216 * This hook is to prepare a framebuffer for scanout by e.g. pinning
1217 * its backing storage or relocating it into a contiguous block of
1218 * VRAM. Other possible preparatory work includes flushing caches.
1219 *
1220 * This function must not block for outstanding rendering, since it is
1221 * called in the context of the atomic IOCTL even for async commits to
1222 * be able to return any errors to userspace. Instead the recommended
1223 * way is to fill out the &drm_plane_state.fence of the passed-in
1224 * &drm_plane_state. If the driver doesn't support native fences then
1225 * equivalent functionality should be implemented through private
1226 * members in the plane structure.
1227 *
1228 * For GEM drivers who neither have a @prepare_fb nor @cleanup_fb hook
1229 * set drm_gem_plane_helper_prepare_fb() is called automatically to
1230 * implement this. Other drivers which need additional plane processing
1231 * can call drm_gem_plane_helper_prepare_fb() from their @prepare_fb
1232 * hook.
1233 *
1234 * The resources acquired in @prepare_fb persist after the end of
1235 * the atomic commit. Resources that can be release at the commit's end
1236 * should be acquired in @begin_fb_access and released in @end_fb_access.
1237 * For example, a GEM buffer's pin operation belongs into @prepare_fb to
1238 * keep the buffer pinned after the commit. But a vmap operation for
1239 * shadow-plane helpers belongs into @begin_fb_access, so that atomic
1240 * helpers remove the mapping at the end of the commit.
1241 *
1242 * The helpers will call @cleanup_fb with matching arguments for every
1243 * successful call to this hook.
1244 *
1245 * This callback is used by the atomic modeset helpers, but it is
1246 * optional. See @begin_fb_access for preparing per-commit resources.
1247 *
1248 * RETURNS:
1249 *
1250 * 0 on success or one of the following negative error codes allowed by
1251 * the &drm_mode_config_funcs.atomic_commit vfunc. When using helpers
1252 * this callback is the only one which can fail an atomic commit,
1253 * everything else must complete successfully.
1254 */
1255 int (*prepare_fb)(struct drm_plane *plane,
1256 struct drm_plane_state *new_state);
1257 /**
1258 * @cleanup_fb:
1259 *
1260 * This hook is called to clean up any resources allocated for the given
1261 * framebuffer and plane configuration in @prepare_fb.
1262 *
1263 * This callback is used by the atomic modeset helpers, but it is
1264 * optional.
1265 */
1266 void (*cleanup_fb)(struct drm_plane *plane,
1267 struct drm_plane_state *old_state);
1268
1269 /**
1270 * @begin_fb_access:
1271 *
1272 * This hook prepares the plane for access during an atomic commit.
1273 * In contrast to @prepare_fb, resources acquired in @begin_fb_access,
1274 * are released at the end of the atomic commit in @end_fb_access.
1275 *
1276 * For example, with shadow-plane helpers, the GEM buffer's vmap
1277 * operation belongs into @begin_fb_access, so that the buffer's
1278 * memory will be unmapped at the end of the commit in @end_fb_access.
1279 * But a GEM buffer's pin operation belongs into @prepare_fb
1280 * to keep the buffer pinned after the commit.
1281 *
1282 * The callback is used by the atomic modeset helpers, but it is optional.
1283 * See @end_fb_cleanup for undoing the effects of @begin_fb_access and
1284 * @prepare_fb for acquiring resources until the next pageflip.
1285 *
1286 * Returns:
1287 * 0 on success, or a negative errno code otherwise.
1288 */
1289 int (*begin_fb_access)(struct drm_plane *plane, struct drm_plane_state *new_plane_state);
1290
1291 /**
1292 * @end_fb_access:
1293 *
1294 * This hook cleans up resources allocated by @begin_fb_access. It it called
1295 * at the end of a commit for the new plane state.
1296 */
1297 void (*end_fb_access)(struct drm_plane *plane, struct drm_plane_state *new_plane_state);
1298
1299 /**
1300 * @atomic_check:
1301 *
1302 * Drivers should check plane specific constraints in this hook.
1303 *
1304 * When using drm_atomic_helper_check_planes() plane's @atomic_check
1305 * hooks are called before the ones for CRTCs, which allows drivers to
1306 * request shared resources that the CRTC controls here. For more
1307 * complicated dependencies the driver can call the provided check helpers
1308 * multiple times until the computed state has a final configuration and
1309 * everything has been checked.
1310 *
1311 * This function is also allowed to inspect any other object's state and
1312 * can add more state objects to the atomic commit if needed. Care must
1313 * be taken though to ensure that state check and compute functions for
1314 * these added states are all called, and derived state in other objects
1315 * all updated. Again the recommendation is to just call check helpers
1316 * until a maximal configuration is reached.
1317 *
1318 * This callback is used by the atomic modeset helpers, but it is
1319 * optional.
1320 *
1321 * NOTE:
1322 *
1323 * This function is called in the check phase of an atomic update. The
1324 * driver is not allowed to change anything outside of the
1325 * &drm_atomic_state update tracking structure.
1326 *
1327 * RETURNS:
1328 *
1329 * 0 on success, -EINVAL if the state or the transition can't be
1330 * supported, -ENOMEM on memory allocation failure and -EDEADLK if an
1331 * attempt to obtain another state object ran into a &drm_modeset_lock
1332 * deadlock.
1333 */
1334 int (*atomic_check)(struct drm_plane *plane,
1335 struct drm_atomic_state *state);
1336
1337 /**
1338 * @atomic_update:
1339 *
1340 * Drivers should use this function to update the plane state. This
1341 * hook is called in-between the &drm_crtc_helper_funcs.atomic_begin and
1342 * drm_crtc_helper_funcs.atomic_flush callbacks.
1343 *
1344 * Note that the power state of the display pipe when this function is
1345 * called depends upon the exact helpers and calling sequence the driver
1346 * has picked. See drm_atomic_helper_commit_planes() for a discussion of
1347 * the tradeoffs and variants of plane commit helpers.
1348 *
1349 * This callback is used by the atomic modeset helpers, but it is optional.
1350 */
1351 void (*atomic_update)(struct drm_plane *plane,
1352 struct drm_atomic_state *state);
1353
1354 /**
1355 * @atomic_enable:
1356 *
1357 * Drivers should use this function to unconditionally enable a plane.
1358 * This hook is called in-between the &drm_crtc_helper_funcs.atomic_begin
1359 * and drm_crtc_helper_funcs.atomic_flush callbacks. It is called after
1360 * @atomic_update, which will be called for all enabled planes. Drivers
1361 * that use @atomic_enable should set up a plane in @atomic_update and
1362 * afterwards enable the plane in @atomic_enable. If a plane needs to be
1363 * enabled before installing the scanout buffer, drivers can still do
1364 * so in @atomic_update.
1365 *
1366 * Note that the power state of the display pipe when this function is
1367 * called depends upon the exact helpers and calling sequence the driver
1368 * has picked. See drm_atomic_helper_commit_planes() for a discussion of
1369 * the tradeoffs and variants of plane commit helpers.
1370 *
1371 * This callback is used by the atomic modeset helpers, but it is
1372 * optional. If implemented, @atomic_enable should be the inverse of
1373 * @atomic_disable. Drivers that don't want to use either can still
1374 * implement the complete plane update in @atomic_update.
1375 */
1376 void (*atomic_enable)(struct drm_plane *plane,
1377 struct drm_atomic_state *state);
1378
1379 /**
1380 * @atomic_disable:
1381 *
1382 * Drivers should use this function to unconditionally disable a plane.
1383 * This hook is called in-between the
1384 * &drm_crtc_helper_funcs.atomic_begin and
1385 * drm_crtc_helper_funcs.atomic_flush callbacks. It is an alternative to
1386 * @atomic_update, which will be called for disabling planes, too, if
1387 * the @atomic_disable hook isn't implemented.
1388 *
1389 * This hook is also useful to disable planes in preparation of a modeset,
1390 * by calling drm_atomic_helper_disable_planes_on_crtc() from the
1391 * &drm_crtc_helper_funcs.disable hook.
1392 *
1393 * Note that the power state of the display pipe when this function is
1394 * called depends upon the exact helpers and calling sequence the driver
1395 * has picked. See drm_atomic_helper_commit_planes() for a discussion of
1396 * the tradeoffs and variants of plane commit helpers.
1397 *
1398 * This callback is used by the atomic modeset helpers, but it is
1399 * optional. It's intended to reverse the effects of @atomic_enable.
1400 */
1401 void (*atomic_disable)(struct drm_plane *plane,
1402 struct drm_atomic_state *state);
1403
1404 /**
1405 * @atomic_async_check:
1406 *
1407 * Drivers should set this function pointer to check if the plane's
1408 * atomic state can be updated in a async fashion. Here async means
1409 * "not vblank synchronized".
1410 *
1411 * This hook is called by drm_atomic_async_check() to establish if a
1412 * given update can be committed asynchronously, that is, if it can
1413 * jump ahead of the state currently queued for update.
1414 *
1415 * This function is also used by drm_atomic_set_property() to determine
1416 * if the plane can be flipped in async. The flip flag is used to
1417 * distinguish if the function is used for just the plane state or for a
1418 * flip.
1419 *
1420 * RETURNS:
1421 *
1422 * Return 0 on success and any error returned indicates that the update
1423 * can not be applied in asynchronous manner.
1424 */
1425 int (*atomic_async_check)(struct drm_plane *plane,
1426 struct drm_atomic_state *state, bool flip);
1427
1428 /**
1429 * @atomic_async_update:
1430 *
1431 * Drivers should set this function pointer to perform asynchronous
1432 * updates of planes, that is, jump ahead of the currently queued
1433 * state and update the plane. Here async means "not vblank
1434 * synchronized".
1435 *
1436 * This hook is called by drm_atomic_helper_async_commit().
1437 *
1438 * An async update will happen on legacy cursor updates. An async
1439 * update won't happen if there is an outstanding commit modifying
1440 * the same plane.
1441 *
1442 * When doing async_update drivers shouldn't replace the
1443 * &drm_plane_state but update the current one with the new plane
1444 * configurations in the new plane_state.
1445 *
1446 * Drivers should also swap the framebuffers between current plane
1447 * state (&drm_plane.state) and new_state.
1448 * This is required since cleanup for async commits is performed on
1449 * the new state, rather than old state like for traditional commits.
1450 * Since we want to give up the reference on the current (old) fb
1451 * instead of our brand new one, swap them in the driver during the
1452 * async commit.
1453 *
1454 * FIXME:
1455 * - It only works for single plane updates
1456 * - Async Pageflips are not supported yet
1457 * - Some hw might still scan out the old buffer until the next
1458 * vblank, however we let go of the fb references as soon as
1459 * we run this hook. For now drivers must implement their own workers
1460 * for deferring if needed, until a common solution is created.
1461 */
1462 void (*atomic_async_update)(struct drm_plane *plane,
1463 struct drm_atomic_state *state);
1464
1465 /**
1466 * @get_scanout_buffer:
1467 *
1468 * Get the current scanout buffer, to display a message with drm_panic.
1469 * The driver should do the minimum changes to provide a buffer,
1470 * that can be used to display the panic screen. Currently only linear
1471 * buffers are supported. Non-linear buffer support is on the TODO list.
1472 * The device &dev.mode_config.panic_lock is taken before calling this
1473 * function, so you can safely access the &plane.state
1474 * It is called from a panic callback, and must follow its restrictions.
1475 * Please look the documentation at drm_panic_trylock() for an in-depth
1476 * discussions of what's safe and what is not allowed.
1477 * It's a best effort mode, so it's expected that in some complex cases
1478 * the panic screen won't be displayed.
1479 * The returned &drm_scanout_buffer.map must be valid if no error code is
1480 * returned.
1481 *
1482 * Return:
1483 * %0 on success, negative errno on failure.
1484 */
1485 int (*get_scanout_buffer)(struct drm_plane *plane,
1486 struct drm_scanout_buffer *sb);
1487
1488 /**
1489 * @panic_flush:
1490 *
1491 * It is used by drm_panic, and is called after the panic screen is
1492 * drawn to the scanout buffer. In this function, the driver
1493 * can send additional commands to the hardware, to make the scanout
1494 * buffer visible.
1495 * It is only called if get_scanout_buffer() returned successfully, and
1496 * the &dev.mode_config.panic_lock is held during the entire sequence.
1497 * It is called from a panic callback, and must follow its restrictions.
1498 * Please look the documentation at drm_panic_trylock() for an in-depth
1499 * discussions of what's safe and what is not allowed.
1500 */
1501 void (*panic_flush)(struct drm_plane *plane);
1502};
1503
1504/**
1505 * drm_plane_helper_add - sets the helper vtable for a plane
1506 * @plane: DRM plane
1507 * @funcs: helper vtable to set for @plane
1508 */
1509static inline void drm_plane_helper_add(struct drm_plane *plane,
1510 const struct drm_plane_helper_funcs *funcs)
1511{
1512 plane->helper_private = funcs;
1513}
1514
1515/**
1516 * struct drm_mode_config_helper_funcs - global modeset helper operations
1517 *
1518 * These helper functions are used by the atomic helpers.
1519 */
1520struct drm_mode_config_helper_funcs {
1521 /**
1522 * @atomic_commit_tail:
1523 *
1524 * This hook is used by the default atomic_commit() hook implemented in
1525 * drm_atomic_helper_commit() together with the nonblocking commit
1526 * helpers (see drm_atomic_helper_setup_commit() for a starting point)
1527 * to implement blocking and nonblocking commits easily. It is not used
1528 * by the atomic helpers
1529 *
1530 * This function is called when the new atomic state has already been
1531 * swapped into the various state pointers. The passed in state
1532 * therefore contains copies of the old/previous state. This hook should
1533 * commit the new state into hardware. Note that the helpers have
1534 * already waited for preceding atomic commits and fences, but drivers
1535 * can add more waiting calls at the start of their implementation, e.g.
1536 * to wait for driver-internal request for implicit syncing, before
1537 * starting to commit the update to the hardware.
1538 *
1539 * After the atomic update is committed to the hardware this hook needs
1540 * to call drm_atomic_helper_commit_hw_done(). Then wait for the update
1541 * to be executed by the hardware, for example using
1542 * drm_atomic_helper_wait_for_vblanks() or
1543 * drm_atomic_helper_wait_for_flip_done(), and then clean up the old
1544 * framebuffers using drm_atomic_helper_cleanup_planes().
1545 *
1546 * When disabling a CRTC this hook _must_ stall for the commit to
1547 * complete. Vblank waits don't work on disabled CRTC, hence the core
1548 * can't take care of this. And it also can't rely on the vblank event,
1549 * since that can be signalled already when the screen shows black,
1550 * which can happen much earlier than the last hardware access needed to
1551 * shut off the display pipeline completely.
1552 *
1553 * This hook is optional, the default implementation is
1554 * drm_atomic_helper_commit_tail().
1555 */
1556 void (*atomic_commit_tail)(struct drm_atomic_state *state);
1557
1558 /**
1559 * @atomic_commit_setup:
1560 *
1561 * This hook is used by the default atomic_commit() hook implemented in
1562 * drm_atomic_helper_commit() together with the nonblocking helpers (see
1563 * drm_atomic_helper_setup_commit()) to extend the DRM commit setup. It
1564 * is not used by the atomic helpers.
1565 *
1566 * This function is called at the end of
1567 * drm_atomic_helper_setup_commit(), so once the commit has been
1568 * properly setup across the generic DRM object states. It allows
1569 * drivers to do some additional commit tracking that isn't related to a
1570 * CRTC, plane or connector, tracked in a &drm_private_obj structure.
1571 *
1572 * Note that the documentation of &drm_private_obj has more details on
1573 * how one should implement this.
1574 *
1575 * This hook is optional.
1576 */
1577 int (*atomic_commit_setup)(struct drm_atomic_state *state);
1578};
1579
1580#endif
1581

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