include/drm/drm_modeset_helper_vtables.h

   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
  51 enum mode_set_atomic;
  52
  53 /**
  54  * struct drm_crtc_helper_funcs - helper operations for CRTCs
  55  *
  56  * These hooks are used by the legacy CRTC helpers, the transitional plane
  57  * helpers and the new atomic modesetting helpers.
  58  */
  59 struct drm_crtc_helper_funcs {
  60         /**
  61          * @dpms:
  62          *
  63          * Callback to control power levels on the CRTC.  If the mode passed in
  64          * is unsupported, the provider must use the next lowest power level.
  65          * This is used by the legacy CRTC helpers to implement DPMS
  66          * functionality in drm_helper_connector_dpms().
  67          *
  68          * This callback is also used to disable a CRTC by calling it with
  69          * DRM_MODE_DPMS_OFF if the @disable hook isn't used.
  70          *
  71          * This callback is used by the legacy CRTC helpers.  Atomic helpers
  72          * also support using this hook for enabling and disabling a CRTC to
  73          * facilitate transitions to atomic, but it is deprecated. Instead
  74          * @enable and @disable should be used.
  75          */
  76         void (*dpms)(struct drm_crtc *crtc, int mode);
  77
  78         /**
  79          * @prepare:
  80          *
  81          * This callback should prepare the CRTC for a subsequent modeset, which
  82          * in practice means the driver should disable the CRTC if it is
  83          * running. Most drivers ended up implementing this by calling their
  84          * @dpms hook with DRM_MODE_DPMS_OFF.
  85          *
  86          * This callback is used by the legacy CRTC helpers.  Atomic helpers
  87          * also support using this hook for disabling a CRTC to facilitate
  88          * transitions to atomic, but it is deprecated. Instead @disable should
  89          * be used.
  90          */
  91         void (*prepare)(struct drm_crtc *crtc);
  92
  93         /**
  94          * @commit:
  95          *
  96          * This callback should commit the new mode on the CRTC after a modeset,
  97          * which in practice means the driver should enable the CRTC.  Most
  98          * drivers ended up implementing this by calling their @dpms hook with
  99          * DRM_MODE_DPMS_ON.
 100          *
 101          * This callback is used by the legacy CRTC helpers.  Atomic helpers
 102          * also support using this hook for enabling a CRTC to facilitate
 103          * transitions to atomic, but it is deprecated. Instead @enable should
 104          * be used.
 105          */
 106         void (*commit)(struct drm_crtc *crtc);
 107
 108         /**
 109          * @mode_fixup:
 110          *
 111          * This callback is used to validate a mode. The parameter mode is the
 112          * display mode that userspace requested, adjusted_mode is the mode the
 113          * encoders need to be fed with. Note that this is the inverse semantics
 114          * of the meaning for the &drm_encoder and &drm_bridge_funcs.mode_fixup
 115          * vfunc. If the CRTC cannot support the requested conversion from mode
 116          * to adjusted_mode it should reject the modeset.
 117          *
 118          * This function is used by both legacy CRTC helpers and atomic helpers.
 119          * With atomic helpers it is optional.
 120          *
 121          * NOTE:
 122          *
 123          * This function is called in the check phase of atomic modesets, which
 124          * can be aborted for any reason (including on userspace's request to
 125          * just check whether a configuration would be possible). Atomic drivers
 126          * MUST NOT touch any persistent state (hardware or software) or data
 127          * structures except the passed in adjusted_mode parameter.
 128          *
 129          * This is in contrast to the legacy CRTC helpers where this was
 130          * allowed.
 131          *
 132          * Atomic drivers which need to inspect and adjust more state should
 133          * instead use the @atomic_check callback.
 134          *
 135          * Also beware that neither core nor helpers filter modes before
 136          * passing them to the driver: While the list of modes that is
 137          * advertised to userspace is filtered using the
 138          * &drm_connector.mode_valid callback, neither the core nor the helpers
 139          * do any filtering on modes passed in from userspace when setting a
 140          * mode. It is therefore possible for userspace to pass in a mode that
 141          * was previously filtered out using &drm_connector.mode_valid or add a
 142          * custom mode that wasn't probed from EDID or similar to begin with.
 143          * Even though this is an advanced feature and rarely used nowadays,
 144          * some users rely on being able to specify modes manually so drivers
 145          * must be prepared to deal with it. Specifically this means that all
 146          * drivers need not only validate modes in &drm_connector.mode_valid but
 147          * also in this or in the &drm_encoder_helper_funcs.mode_fixup callback
 148          * to make sure invalid modes passed in from userspace are rejected.
 149          *
 150          * RETURNS:
 151          *
 152          * True if an acceptable configuration is possible, false if the modeset
 153          * operation should be rejected.
 154          */
 155         bool (*mode_fixup)(struct drm_crtc *crtc,
 156                            const struct drm_display_mode *mode,
 157                            struct drm_display_mode *adjusted_mode);
 158
 159         /**
 160          * @mode_set:
 161          *
 162          * This callback is used by the legacy CRTC helpers to set a new mode,
 163          * position and framebuffer. Since it ties the primary plane to every
 164          * mode change it is incompatible with universal plane support. And
 165          * since it can't update other planes it's incompatible with atomic
 166          * modeset support.
 167          *
 168          * This callback is only used by CRTC helpers and deprecated.
 169          *
 170          * RETURNS:
 171          *
 172          * 0 on success or a negative error code on failure.
 173          */
 174         int (*mode_set)(struct drm_crtc *crtc, struct drm_display_mode *mode,
 175                         struct drm_display_mode *adjusted_mode, int x, int y,
 176                         struct drm_framebuffer *old_fb);
 177
 178         /**
 179          * @mode_set_nofb:
 180          *
 181          * This callback is used to update the display mode of a CRTC without
 182          * changing anything of the primary plane configuration. This fits the
 183          * requirement of atomic and hence is used by the atomic helpers. It is
 184          * also used by the transitional plane helpers to implement a
 185          * @mode_set hook in drm_helper_crtc_mode_set().
 186          *
 187          * Note that the display pipe is completely off when this function is
 188          * called. Atomic drivers which need hardware to be running before they
 189          * program the new display mode (e.g. because they implement runtime PM)
 190          * should not use this hook. This is because the helper library calls
 191          * this hook only once per mode change and not every time the display
 192          * pipeline is suspended using either DPMS or the new "ACTIVE" property.
 193          * Which means register values set in this callback might get reset when
 194          * the CRTC is suspended, but not restored.  Such drivers should instead
 195          * move all their CRTC setup into the @enable callback.
 196          *
 197          * This callback is optional.
 198          */
 199         void (*mode_set_nofb)(struct drm_crtc *crtc);
 200
 201         /**
 202          * @mode_set_base:
 203          *
 204          * This callback is used by the legacy CRTC helpers to set a new
 205          * framebuffer and scanout position. It is optional and used as an
 206          * optimized fast-path instead of a full mode set operation with all the
 207          * resulting flickering. If it is not present
 208          * drm_crtc_helper_set_config() will fall back to a full modeset, using
 209          * the @mode_set callback. Since it can't update other planes it's
 210          * incompatible with atomic modeset support.
 211          *
 212          * This callback is only used by the CRTC helpers and deprecated.
 213          *
 214          * RETURNS:
 215          *
 216          * 0 on success or a negative error code on failure.
 217          */
 218         int (*mode_set_base)(struct drm_crtc *crtc, int x, int y,
 219                              struct drm_framebuffer *old_fb);
 220
 221         /**
 222          * @mode_set_base_atomic:
 223          *
 224          * This callback is used by the fbdev helpers to set a new framebuffer
 225          * and scanout without sleeping, i.e. from an atomic calling context. It
 226          * is only used to implement kgdb support.
 227          *
 228          * This callback is optional and only needed for kgdb support in the fbdev
 229          * helpers.
 230          *
 231          * RETURNS:
 232          *
 233          * 0 on success or a negative error code on failure.
 234          */
 235         int (*mode_set_base_atomic)(struct drm_crtc *crtc,
 236                                     struct drm_framebuffer *fb, int x, int y,
 237                                     enum mode_set_atomic);
 238
 239         /**
 240          * @load_lut:
 241          *
 242          * Load a LUT prepared with the &drm_fb_helper_funcs.gamma_set vfunc.
 243          *
 244          * This callback is optional and is only used by the fbdev emulation
 245          * helpers.
 246          *
 247          * FIXME:
 248          *
 249          * This callback is functionally redundant with the core gamma table
 250          * support and simply exists because the fbdev hasn't yet been
 251          * refactored to use the core gamma table interfaces.
 252          */
 253         void (*load_lut)(struct drm_crtc *crtc);
 254
 255         /**
 256          * @disable:
 257          *
 258          * This callback should be used to disable the CRTC. With the atomic
 259          * drivers it is called after all encoders connected to this CRTC have
 260          * been shut off already using their own
 261          * &drm_encoder_helper_funcs.disable hook. If that sequence is too
 262          * simple drivers can just add their own hooks and call it from this
 263          * CRTC callback here by looping over all encoders connected to it using
 264          * for_each_encoder_on_crtc().
 265          *
 266          * This hook is used both by legacy CRTC helpers and atomic helpers.
 267          * Atomic drivers don't need to implement it if there's no need to
 268          * disable anything at the CRTC level. To ensure that runtime PM
 269          * handling (using either DPMS or the new "ACTIVE" property) works
 270          * @disable must be the inverse of @enable for atomic drivers.
 271          * Atomic drivers should consider to use @atomic_disable instead of
 272          * this one.
 273          *
 274          * NOTE:
 275          *
 276          * With legacy CRTC helpers there's a big semantic difference between
 277          * @disable and other hooks (like @prepare or @dpms) used to shut down a
 278          * CRTC: @disable is only called when also logically disabling the
 279          * display pipeline and needs to release any resources acquired in
 280          * @mode_set (like shared PLLs, or again release pinned framebuffers).
 281          *
 282          * Therefore @disable must be the inverse of @mode_set plus @commit for
 283          * drivers still using legacy CRTC helpers, which is different from the
 284          * rules under atomic.
 285          */
 286         void (*disable)(struct drm_crtc *crtc);
 287
 288         /**
 289          * @enable:
 290          *
 291          * This callback should be used to enable the CRTC. With the atomic
 292          * drivers it is called before all encoders connected to this CRTC are
 293          * enabled through the encoder's own &drm_encoder_helper_funcs.enable
 294          * hook.  If that sequence is too simple drivers can just add their own
 295          * hooks and call it from this CRTC callback here by looping over all
 296          * encoders connected to it using for_each_encoder_on_crtc().
 297          *
 298          * This hook is used only by atomic helpers, for symmetry with @disable.
 299          * Atomic drivers don't need to implement it if there's no need to
 300          * enable anything at the CRTC level. To ensure that runtime PM handling
 301          * (using either DPMS or the new "ACTIVE" property) works
 302          * @enable must be the inverse of @disable for atomic drivers.
 303          */
 304         void (*enable)(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.atomc_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 and by the
 335          * transitional plane helpers, but it is 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 objects passed-in or assembled in the overall &drm_atomic_state
 342          * update tracking structure.
 343          *
 344          * RETURNS:
 345          *
 346          * 0 on success, -EINVAL if the state or the transition can't be
 347          * supported, -ENOMEM on memory allocation failure and -EDEADLK if an
 348          * attempt to obtain another state object ran into a &drm_modeset_lock
 349          * deadlock.
 350          */
 351         int (*atomic_check)(struct drm_crtc *crtc,
 352                             struct drm_crtc_state *state);
 353
 354         /**
 355          * @atomic_begin:
 356          *
 357          * Drivers should prepare for an atomic update of multiple planes on
 358          * a CRTC in this hook. Depending upon hardware this might be vblank
 359          * evasion, blocking updates by setting bits or doing preparatory work
 360          * for e.g. manual update display.
 361          *
 362          * This hook is called before any plane commit functions are called.
 363          *
 364          * Note that the power state of the display pipe when this function is
 365          * called depends upon the exact helpers and calling sequence the driver
 366          * has picked. See drm_atomic_helper_commit_planes() for a discussion of
 367          * the tradeoffs and variants of plane commit helpers.
 368          *
 369          * This callback is used by the atomic modeset helpers and by the
 370          * transitional plane helpers, but it is optional.
 371          */
 372         void (*atomic_begin)(struct drm_crtc *crtc,
 373                              struct drm_crtc_state *old_crtc_state);
 374         /**
 375          * @atomic_flush:
 376          *
 377          * Drivers should finalize an atomic update of multiple planes on
 378          * a CRTC in this hook. Depending upon hardware this might include
 379          * checking that vblank evasion was successful, unblocking updates by
 380          * setting bits or setting the GO bit to flush out all updates.
 381          *
 382          * Simple hardware or hardware with special requirements can commit and
 383          * flush out all updates for all planes from this hook and forgo all the
 384          * other commit hooks for plane updates.
 385          *
 386          * This hook is called after any plane commit functions are called.
 387          *
 388          * Note that the power state of the display pipe when this function is
 389          * called depends upon the exact helpers and calling sequence the driver
 390          * has picked. See drm_atomic_helper_commit_planes() for a discussion of
 391          * the tradeoffs and variants of plane commit helpers.
 392          *
 393          * This callback is used by the atomic modeset helpers and by the
 394          * transitional plane helpers, but it is optional.
 395          */
 396         void (*atomic_flush)(struct drm_crtc *crtc,
 397                              struct drm_crtc_state *old_crtc_state);
 398
 399         /**
 400          * @atomic_disable:
 401          *
 402          * This callback should be used to disable the CRTC. With the atomic
 403          * drivers it is called after all encoders connected to this CRTC have
 404          * been shut off already using their own
 405          * &drm_encoder_helper_funcs.disable hook. If that sequence is too
 406          * simple drivers can just add their own hooks and call it from this
 407          * CRTC callback here by looping over all encoders connected to it using
 408          * for_each_encoder_on_crtc().
 409          *
 410          * This hook is used only by atomic helpers. Atomic drivers don't
 411          * need to implement it if there's no need to disable anything at the
 412          * CRTC level.
 413          *
 414          * Comparing to @disable, this one provides the additional input
 415          * parameter @old_crtc_state which could be used to access the old
 416          * state. Atomic drivers should consider to use this one instead
 417          * of @disable.
 418          */
 419         void (*atomic_disable)(struct drm_crtc *crtc,
 420                                struct drm_crtc_state *old_crtc_state);
 421 };
 422
 423 /**
 424  * drm_crtc_helper_add - sets the helper vtable for a crtc
 425  * @crtc: DRM CRTC
 426  * @funcs: helper vtable to set for @crtc
 427  */
 428 static inline void drm_crtc_helper_add(struct drm_crtc *crtc,
 429                                        const struct drm_crtc_helper_funcs *funcs)
 430 {
 431         crtc->helper_private = funcs;
 432 }
 433
 434 /**
 435  * struct drm_encoder_helper_funcs - helper operations for encoders
 436  *
 437  * These hooks are used by the legacy CRTC helpers, the transitional plane
 438  * helpers and the new atomic modesetting helpers.
 439  */
 440 struct drm_encoder_helper_funcs {
 441         /**
 442          * @dpms:
 443          *
 444          * Callback to control power levels on the encoder.  If the mode passed in
 445          * is unsupported, the provider must use the next lowest power level.
 446          * This is used by the legacy encoder helpers to implement DPMS
 447          * functionality in drm_helper_connector_dpms().
 448          *
 449          * This callback is also used to disable an encoder by calling it with
 450          * DRM_MODE_DPMS_OFF if the @disable hook isn't used.
 451          *
 452          * This callback is used by the legacy CRTC helpers.  Atomic helpers
 453          * also support using this hook for enabling and disabling an encoder to
 454          * facilitate transitions to atomic, but it is deprecated. Instead
 455          * @enable and @disable should be used.
 456          */
 457         void (*dpms)(struct drm_encoder *encoder, int mode);
 458
 459         /**
 460          * @mode_fixup:
 461          *
 462          * This callback is used to validate and adjust a mode. The parameter
 463          * mode is the display mode that should be fed to the next element in
 464          * the display chain, either the final &drm_connector or a &drm_bridge.
 465          * The parameter adjusted_mode is the input mode the encoder requires. It
 466          * can be modified by this callback and does not need to match mode.
 467          *
 468          * This function is used by both legacy CRTC helpers and atomic helpers.
 469          * This hook is optional.
 470          *
 471          * NOTE:
 472          *
 473          * This function is called in the check phase of atomic modesets, which
 474          * can be aborted for any reason (including on userspace's request to
 475          * just check whether a configuration would be possible). Atomic drivers
 476          * MUST NOT touch any persistent state (hardware or software) or data
 477          * structures except the passed in adjusted_mode parameter.
 478          *
 479          * This is in contrast to the legacy CRTC helpers where this was
 480          * allowed.
 481          *
 482          * Atomic drivers which need to inspect and adjust more state should
 483          * instead use the @atomic_check callback.
 484          *
 485          * Also beware that neither core nor helpers filter modes before
 486          * passing them to the driver: While the list of modes that is
 487          * advertised to userspace is filtered using the connector's
 488          * &drm_connector_helper_funcs.mode_valid callback, neither the core nor
 489          * the helpers do any filtering on modes passed in from userspace when
 490          * setting a mode. It is therefore possible for userspace to pass in a
 491          * mode that was previously filtered out using
 492          * &drm_connector_helper_funcs.mode_valid or add a custom mode that
 493          * wasn't probed from EDID or similar to begin with.  Even though this
 494          * is an advanced feature and rarely used nowadays, some users rely on
 495          * being able to specify modes manually so drivers must be prepared to
 496          * deal with it. Specifically this means that all drivers need not only
 497          * validate modes in &drm_connector.mode_valid but also in this or in
 498          * the &drm_crtc_helper_funcs.mode_fixup callback to make sure
 499          * invalid modes passed in from userspace are rejected.
 500          *
 501          * RETURNS:
 502          *
 503          * True if an acceptable configuration is possible, false if the modeset
 504          * operation should be rejected.
 505          */
 506         bool (*mode_fixup)(struct drm_encoder *encoder,
 507                            const struct drm_display_mode *mode,
 508                            struct drm_display_mode *adjusted_mode);
 509
 510         /**
 511          * @prepare:
 512          *
 513          * This callback should prepare the encoder for a subsequent modeset,
 514          * which in practice means the driver should disable the encoder if it
 515          * is running. Most drivers ended up implementing this by calling their
 516          * @dpms hook with DRM_MODE_DPMS_OFF.
 517          *
 518          * This callback is used by the legacy CRTC helpers.  Atomic helpers
 519          * also support using this hook for disabling an encoder to facilitate
 520          * transitions to atomic, but it is deprecated. Instead @disable should
 521          * be used.
 522          */
 523         void (*prepare)(struct drm_encoder *encoder);
 524
 525         /**
 526          * @commit:
 527          *
 528          * This callback should commit the new mode on the encoder after a modeset,
 529          * which in practice means the driver should enable the encoder.  Most
 530          * drivers ended up implementing this by calling their @dpms hook with
 531          * DRM_MODE_DPMS_ON.
 532          *
 533          * This callback is used by the legacy CRTC helpers.  Atomic helpers
 534          * also support using this hook for enabling an encoder to facilitate
 535          * transitions to atomic, but it is deprecated. Instead @enable should
 536          * be used.
 537          */
 538         void (*commit)(struct drm_encoder *encoder);
 539
 540         /**
 541          * @mode_set:
 542          *
 543          * This callback is used to update the display mode of an encoder.
 544          *
 545          * Note that the display pipe is completely off when this function is
 546          * called. Drivers which need hardware to be running before they program
 547          * the new display mode (because they implement runtime PM) should not
 548          * use this hook, because the helper library calls it only once and not
 549          * every time the display pipeline is suspend using either DPMS or the
 550          * new "ACTIVE" property. Such drivers should instead move all their
 551          * encoder setup into the @enable callback.
 552          *
 553          * This callback is used both by the legacy CRTC helpers and the atomic
 554          * modeset helpers. It is optional in the atomic helpers.
 555          *
 556          * NOTE:
 557          *
 558          * If the driver uses the atomic modeset helpers and needs to inspect
 559          * the connector state or connector display info during mode setting,
 560          * @atomic_mode_set can be used instead.
 561          */
 562         void (*mode_set)(struct drm_encoder *encoder,
 563                          struct drm_display_mode *mode,
 564                          struct drm_display_mode *adjusted_mode);
 565
 566         /**
 567          * @atomic_mode_set:
 568          *
 569          * This callback is used to update the display mode of an encoder.
 570          *
 571          * Note that the display pipe is completely off when this function is
 572          * called. Drivers which need hardware to be running before they program
 573          * the new display mode (because they implement runtime PM) should not
 574          * use this hook, because the helper library calls it only once and not
 575          * every time the display pipeline is suspended using either DPMS or the
 576          * new "ACTIVE" property. Such drivers should instead move all their
 577          * encoder setup into the @enable callback.
 578          *
 579          * This callback is used by the atomic modeset helpers in place of the
 580          * @mode_set callback, if set by the driver. It is optional and should
 581          * be used instead of @mode_set if the driver needs to inspect the
 582          * connector state or display info, since there is no direct way to
 583          * go from the encoder to the current connector.
 584          */
 585         void (*atomic_mode_set)(struct drm_encoder *encoder,
 586                                 struct drm_crtc_state *crtc_state,
 587                                 struct drm_connector_state *conn_state);
 588
 589         /**
 590          * @get_crtc:
 591          *
 592          * This callback is used by the legacy CRTC helpers to work around
 593          * deficiencies in its own book-keeping.
 594          *
 595          * Do not use, use atomic helpers instead, which get the book keeping
 596          * right.
 597          *
 598          * FIXME:
 599          *
 600          * Currently only nouveau is using this, and as soon as nouveau is
 601          * atomic we can ditch this hook.
 602          */
 603         struct drm_crtc *(*get_crtc)(struct drm_encoder *encoder);
 604
 605         /**
 606          * @detect:
 607          *
 608          * This callback can be used by drivers who want to do detection on the
 609          * encoder object instead of in connector functions.
 610          *
 611          * It is not used by any helper and therefore has purely driver-specific
 612          * semantics. New drivers shouldn't use this and instead just implement
 613          * their own private callbacks.
 614          *
 615          * FIXME:
 616          *
 617          * This should just be converted into a pile of driver vfuncs.
 618          * Currently radeon, amdgpu and nouveau are using it.
 619          */
 620         enum drm_connector_status (*detect)(struct drm_encoder *encoder,
 621                                             struct drm_connector *connector);
 622
 623         /**
 624          * @disable:
 625          *
 626          * This callback should be used to disable the encoder. With the atomic
 627          * drivers it is called before this encoder's CRTC has been shut off
 628          * using their own &drm_crtc_helper_funcs.disable hook.  If that
 629          * sequence is too simple drivers can just add their own driver private
 630          * encoder hooks and call them from CRTC's callback by looping over all
 631          * encoders connected to it using for_each_encoder_on_crtc().
 632          *
 633          * This hook is used both by legacy CRTC helpers and atomic helpers.
 634          * Atomic drivers don't need to implement it if there's no need to
 635          * disable anything at the encoder level. To ensure that runtime PM
 636          * handling (using either DPMS or the new "ACTIVE" property) works
 637          * @disable must be the inverse of @enable for atomic drivers.
 638          *
 639          * NOTE:
 640          *
 641          * With legacy CRTC helpers there's a big semantic difference between
 642          * @disable and other hooks (like @prepare or @dpms) used to shut down a
 643          * encoder: @disable is only called when also logically disabling the
 644          * display pipeline and needs to release any resources acquired in
 645          * @mode_set (like shared PLLs, or again release pinned framebuffers).
 646          *
 647          * Therefore @disable must be the inverse of @mode_set plus @commit for
 648          * drivers still using legacy CRTC helpers, which is different from the
 649          * rules under atomic.
 650          */
 651         void (*disable)(struct drm_encoder *encoder);
 652
 653         /**
 654          * @enable:
 655          *
 656          * This callback should be used to enable the encoder. With the atomic
 657          * drivers it is called after this encoder's CRTC has been enabled using
 658          * their own &drm_crtc_helper_funcs.enable hook.  If that sequence is
 659          * too simple drivers can just add their own driver private encoder
 660          * hooks and call them from CRTC's callback by looping over all encoders
 661          * connected to it using for_each_encoder_on_crtc().
 662          *
 663          * This hook is used only by atomic helpers, for symmetry with @disable.
 664          * Atomic drivers don't need to implement it if there's no need to
 665          * enable anything at the encoder level. To ensure that runtime PM handling
 666          * (using either DPMS or the new "ACTIVE" property) works
 667          * @enable must be the inverse of @disable for atomic drivers.
 668          */
 669         void (*enable)(struct drm_encoder *encoder);
 670
 671         /**
 672          * @atomic_check:
 673          *
 674          * This callback is used to validate encoder state for atomic drivers.
 675          * Since the encoder is the object connecting the CRTC and connector it
 676          * gets passed both states, to be able to validate interactions and
 677          * update the CRTC to match what the encoder needs for the requested
 678          * connector.
 679          *
 680          * This function is used by the atomic helpers, but it is optional.
 681          *
 682          * NOTE:
 683          *
 684          * This function is called in the check phase of an atomic update. The
 685          * driver is not allowed to change anything outside of the free-standing
 686          * state objects passed-in or assembled in the overall &drm_atomic_state
 687          * update tracking structure.
 688          *
 689          * RETURNS:
 690          *
 691          * 0 on success, -EINVAL if the state or the transition can't be
 692          * supported, -ENOMEM on memory allocation failure and -EDEADLK if an
 693          * attempt to obtain another state object ran into a &drm_modeset_lock
 694          * deadlock.
 695          */
 696         int (*atomic_check)(struct drm_encoder *encoder,
 697                             struct drm_crtc_state *crtc_state,
 698                             struct drm_connector_state *conn_state);
 699 };
 700
 701 /**
 702  * drm_encoder_helper_add - sets the helper vtable for an encoder
 703  * @encoder: DRM encoder
 704  * @funcs: helper vtable to set for @encoder
 705  */
 706 static inline void drm_encoder_helper_add(struct drm_encoder *encoder,
 707                                           const struct drm_encoder_helper_funcs *funcs)
 708 {
 709         encoder->helper_private = funcs;
 710 }
 711
 712 /**
 713  * struct drm_connector_helper_funcs - helper operations for connectors
 714  *
 715  * These functions are used by the atomic and legacy modeset helpers and by the
 716  * probe helpers.
 717  */
 718 struct drm_connector_helper_funcs {
 719         /**
 720          * @get_modes:
 721          *
 722          * This function should fill in all modes currently valid for the sink
 723          * into the &drm_connector.probed_modes list. It should also update the
 724          * EDID property by calling drm_mode_connector_update_edid_property().
 725          *
 726          * The usual way to implement this is to cache the EDID retrieved in the
 727          * probe callback somewhere in the driver-private connector structure.
 728          * In this function drivers then parse the modes in the EDID and add
 729          * them by calling drm_add_edid_modes(). But connectors that driver a
 730          * fixed panel can also manually add specific modes using
 731          * drm_mode_probed_add(). Drivers which manually add modes should also
 732          * make sure that the &drm_connector.display_info,
 733          * &drm_connector.width_mm and &drm_connector.height_mm fields are
 734          * filled in.
 735          *
 736          * Virtual drivers that just want some standard VESA mode with a given
 737          * resolution can call drm_add_modes_noedid(), and mark the preferred
 738          * one using drm_set_preferred_mode().
 739          *
 740          * Finally drivers that support audio probably want to update the ELD
 741          * data, too, using drm_edid_to_eld().
 742          *
 743          * This function is only called after the @detect hook has indicated
 744          * that a sink is connected and when the EDID isn't overridden through
 745          * sysfs or the kernel commandline.
 746          *
 747          * This callback is used by the probe helpers in e.g.
 748          * drm_helper_probe_single_connector_modes().
 749          *
 750          * To avoid races with concurrent connector state updates, the helper
 751          * libraries always call this with the &drm_mode_config.connection_mutex
 752          * held. Because of this it's safe to inspect &drm_connector->state.
 753          *
 754          * RETURNS:
 755          *
 756          * The number of modes added by calling drm_mode_probed_add().
 757          */
 758         int (*get_modes)(struct drm_connector *connector);
 759
 760         /**
 761          * @detect_ctx:
 762          *
 763          * Check to see if anything is attached to the connector. The parameter
 764          * force is set to false whilst polling, true when checking the
 765          * connector due to a user request. force can be used by the driver to
 766          * avoid expensive, destructive operations during automated probing.
 767          *
 768          * This callback is optional, if not implemented the connector will be
 769          * considered as always being attached.
 770          *
 771          * This is the atomic version of &drm_connector_funcs.detect.
 772          *
 773          * To avoid races against concurrent connector state updates, the
 774          * helper libraries always call this with ctx set to a valid context,
 775          * and &drm_mode_config.connection_mutex will always be locked with
 776          * the ctx parameter set to this ctx. This allows taking additional
 777          * locks as required.
 778          *
 779          * RETURNS:
 780          *
 781          * &drm_connector_status indicating the connector's status,
 782          * or the error code returned by drm_modeset_lock(), -EDEADLK.
 783          */
 784         int (*detect_ctx)(struct drm_connector *connector,
 785                           struct drm_modeset_acquire_ctx *ctx,
 786                           bool force);
 787
 788         /**
 789          * @mode_valid:
 790          *
 791          * Callback to validate a mode for a connector, irrespective of the
 792          * specific display configuration.
 793          *
 794          * This callback is used by the probe helpers to filter the mode list
 795          * (which is usually derived from the EDID data block from the sink).
 796          * See e.g. drm_helper_probe_single_connector_modes().
 797          *
 798          * NOTE:
 799          *
 800          * This only filters the mode list supplied to userspace in the
 801          * GETCONNECOTR IOCTL. Userspace is free to create modes of its own and
 802          * ask the kernel to use them. It this case the atomic helpers or legacy
 803          * CRTC helpers will not call this function. Drivers therefore must
 804          * still fully validate any mode passed in in a modeset request.
 805          *
 806          * To avoid races with concurrent connector state updates, the helper
 807          * libraries always call this with the &drm_mode_config.connection_mutex
 808          * held. Because of this it's safe to inspect &drm_connector->state.
 809          *
 810          * RETURNS:
 811          *
 812          * Either &drm_mode_status.MODE_OK or one of the failure reasons in &enum
 813          * drm_mode_status.
 814          */
 815         enum drm_mode_status (*mode_valid)(struct drm_connector *connector,
 816                                            struct drm_display_mode *mode);
 817         /**
 818          * @best_encoder:
 819          *
 820          * This function should select the best encoder for the given connector.
 821          *
 822          * This function is used by both the atomic helpers (in the
 823          * drm_atomic_helper_check_modeset() function) and in the legacy CRTC
 824          * helpers.
 825          *
 826          * NOTE:
 827          *
 828          * In atomic drivers this function is called in the check phase of an
 829          * atomic update. The driver is not allowed to change or inspect
 830          * anything outside of arguments passed-in. Atomic drivers which need to
 831          * inspect dynamic configuration state should instead use
 832          * @atomic_best_encoder.
 833          *
 834          * You can leave this function to NULL if the connector is only
 835          * attached to a single encoder and you are using the atomic helpers.
 836          * In this case, the core will call drm_atomic_helper_best_encoder()
 837          * for you.
 838          *
 839          * RETURNS:
 840          *
 841          * Encoder that should be used for the given connector and connector
 842          * state, or NULL if no suitable encoder exists. Note that the helpers
 843          * will ensure that encoders aren't used twice, drivers should not check
 844          * for this.
 845          */
 846         struct drm_encoder *(*best_encoder)(struct drm_connector *connector);
 847
 848         /**
 849          * @atomic_best_encoder:
 850          *
 851          * This is the atomic version of @best_encoder for atomic drivers which
 852          * need to select the best encoder depending upon the desired
 853          * configuration and can't select it statically.
 854          *
 855          * This function is used by drm_atomic_helper_check_modeset().
 856          * If it is not implemented, the core will fallback to @best_encoder
 857          * (or drm_atomic_helper_best_encoder() if @best_encoder is NULL).
 858          *
 859          * NOTE:
 860          *
 861          * This function is called in the check phase of an atomic update. The
 862          * driver is not allowed to change anything outside of the free-standing
 863          * state objects passed-in or assembled in the overall &drm_atomic_state
 864          * update tracking structure.
 865          *
 866          * RETURNS:
 867          *
 868          * Encoder that should be used for the given connector and connector
 869          * state, or NULL if no suitable encoder exists. Note that the helpers
 870          * will ensure that encoders aren't used twice, drivers should not check
 871          * for this.
 872          */
 873         struct drm_encoder *(*atomic_best_encoder)(struct drm_connector *connector,
 874                                                    struct drm_connector_state *connector_state);
 875
 876         /**
 877          * @atomic_check:
 878          *
 879          * This hook is used to validate connector state. This function is
 880          * called from &drm_atomic_helper_check_modeset, and is called when
 881          * a connector property is set, or a modeset on the crtc is forced.
 882          *
 883          * Because &drm_atomic_helper_check_modeset may be called multiple times,
 884          * this function should handle being called multiple times as well.
 885          *
 886          * This function is also allowed to inspect any other object's state and
 887          * can add more state objects to the atomic commit if needed. Care must
 888          * be taken though to ensure that state check and compute functions for
 889          * these added states are all called, and derived state in other objects
 890          * all updated. Again the recommendation is to just call check helpers
 891          * until a maximal configuration is reached.
 892          *
 893          * NOTE:
 894          *
 895          * This function is called in the check phase of an atomic update. The
 896          * driver is not allowed to change anything outside of the free-standing
 897          * state objects passed-in or assembled in the overall &drm_atomic_state
 898          * update tracking structure.
 899          *
 900          * RETURNS:
 901          *
 902          * 0 on success, -EINVAL if the state or the transition can't be
 903          * supported, -ENOMEM on memory allocation failure and -EDEADLK if an
 904          * attempt to obtain another state object ran into a &drm_modeset_lock
 905          * deadlock.
 906          */
 907         int (*atomic_check)(struct drm_connector *connector,
 908                             struct drm_connector_state *state);
 909 };
 910
 911 /**
 912  * drm_connector_helper_add - sets the helper vtable for a connector
 913  * @connector: DRM connector
 914  * @funcs: helper vtable to set for @connector
 915  */
 916 static inline void drm_connector_helper_add(struct drm_connector *connector,
 917                                             const struct drm_connector_helper_funcs *funcs)
 918 {
 919         connector->helper_private = funcs;
 920 }
 921
 922 /**
 923  * struct drm_plane_helper_funcs - helper operations for planes
 924  *
 925  * These functions are used by the atomic helpers and by the transitional plane
 926  * helpers.
 927  */
 928 struct drm_plane_helper_funcs {
 929         /**
 930          * @prepare_fb:
 931          *
 932          * This hook is to prepare a framebuffer for scanout by e.g. pinning
 933          * it's backing storage or relocating it into a contiguous block of
 934          * VRAM. Other possible preparatory work includes flushing caches.
 935          *
 936          * This function must not block for outstanding rendering, since it is
 937          * called in the context of the atomic IOCTL even for async commits to
 938          * be able to return any errors to userspace. Instead the recommended
 939          * way is to fill out the fence member of the passed-in
 940          * &drm_plane_state. If the driver doesn't support native fences then
 941          * equivalent functionality should be implemented through private
 942          * members in the plane structure.
 943          *
 944          * The helpers will call @cleanup_fb with matching arguments for every
 945          * successful call to this hook.
 946          *
 947          * This callback is used by the atomic modeset helpers and by the
 948          * transitional plane helpers, but it is optional.
 949          *
 950          * RETURNS:
 951          *
 952          * 0 on success or one of the following negative error codes allowed by
 953          * the &drm_mode_config_funcs.atomic_commit vfunc. When using helpers
 954          * this callback is the only one which can fail an atomic commit,
 955          * everything else must complete successfully.
 956          */
 957         int (*prepare_fb)(struct drm_plane *plane,
 958                           struct drm_plane_state *new_state);
 959         /**
 960          * @cleanup_fb:
 961          *
 962          * This hook is called to clean up any resources allocated for the given
 963          * framebuffer and plane configuration in @prepare_fb.
 964          *
 965          * This callback is used by the atomic modeset helpers and by the
 966          * transitional plane helpers, but it is optional.
 967          */
 968         void (*cleanup_fb)(struct drm_plane *plane,
 969                            struct drm_plane_state *old_state);
 970
 971         /**
 972          * @atomic_check:
 973          *
 974          * Drivers should check plane specific constraints in this hook.
 975          *
 976          * When using drm_atomic_helper_check_planes() plane's @atomic_check
 977          * hooks are called before the ones for CRTCs, which allows drivers to
 978          * request shared resources that the CRTC controls here. For more
 979          * complicated dependencies the driver can call the provided check helpers
 980          * multiple times until the computed state has a final configuration and
 981          * everything has been checked.
 982          *
 983          * This function is also allowed to inspect any other object's state and
 984          * can add more state objects to the atomic commit if needed. Care must
 985          * be taken though to ensure that state check and compute functions for
 986          * these added states are all called, and derived state in other objects
 987          * all updated. Again the recommendation is to just call check helpers
 988          * until a maximal configuration is reached.
 989          *
 990          * This callback is used by the atomic modeset helpers and by the
 991          * transitional plane helpers, but it is optional.
 992          *
 993          * NOTE:
 994          *
 995          * This function is called in the check phase of an atomic update. The
 996          * driver is not allowed to change anything outside of the free-standing
 997          * state objects passed-in or assembled in the overall &drm_atomic_state
 998          * update tracking structure.
 999          *
1000          * RETURNS:
1001          *
1002          * 0 on success, -EINVAL if the state or the transition can't be
1003          * supported, -ENOMEM on memory allocation failure and -EDEADLK if an
1004          * attempt to obtain another state object ran into a &drm_modeset_lock
1005          * deadlock.
1006          */
1007         int (*atomic_check)(struct drm_plane *plane,
1008                             struct drm_plane_state *state);
1009
1010         /**
1011          * @atomic_update:
1012          *
1013          * Drivers should use this function to update the plane state.  This
1014          * hook is called in-between the &drm_crtc_helper_funcs.atomic_begin and
1015          * drm_crtc_helper_funcs.atomic_flush callbacks.
1016          *
1017          * Note that the power state of the display pipe when this function is
1018          * called depends upon the exact helpers and calling sequence the driver
1019          * has picked. See drm_atomic_helper_commit_planes() for a discussion of
1020          * the tradeoffs and variants of plane commit helpers.
1021          *
1022          * This callback is used by the atomic modeset helpers and by the
1023          * transitional plane helpers, but it is optional.
1024          */
1025         void (*atomic_update)(struct drm_plane *plane,
1026                               struct drm_plane_state *old_state);
1027         /**
1028          * @atomic_disable:
1029          *
1030          * Drivers should use this function to unconditionally disable a plane.
1031          * This hook is called in-between the
1032          * &drm_crtc_helper_funcs.atomic_begin and
1033          * drm_crtc_helper_funcs.atomic_flush callbacks. It is an alternative to
1034          * @atomic_update, which will be called for disabling planes, too, if
1035          * the @atomic_disable hook isn't implemented.
1036          *
1037          * This hook is also useful to disable planes in preparation of a modeset,
1038          * by calling drm_atomic_helper_disable_planes_on_crtc() from the
1039          * &drm_crtc_helper_funcs.disable hook.
1040          *
1041          * Note that the power state of the display pipe when this function is
1042          * called depends upon the exact helpers and calling sequence the driver
1043          * has picked. See drm_atomic_helper_commit_planes() for a discussion of
1044          * the tradeoffs and variants of plane commit helpers.
1045          *
1046          * This callback is used by the atomic modeset helpers and by the
1047          * transitional plane helpers, but it is optional.
1048          */
1049         void (*atomic_disable)(struct drm_plane *plane,
1050                                struct drm_plane_state *old_state);
1051 };
1052
1053 /**
1054  * drm_plane_helper_add - sets the helper vtable for a plane
1055  * @plane: DRM plane
1056  * @funcs: helper vtable to set for @plane
1057  */
1058 static inline void drm_plane_helper_add(struct drm_plane *plane,
1059                                         const struct drm_plane_helper_funcs *funcs)
1060 {
1061         plane->helper_private = funcs;
1062 }
1063
1064 /**
1065  * struct drm_mode_config_helper_funcs - global modeset helper operations
1066  *
1067  * These helper functions are used by the atomic helpers.
1068  */
1069 struct drm_mode_config_helper_funcs {
1070         /**
1071          * @atomic_commit_tail:
1072          *
1073          * This hook is used by the default atomic_commit() hook implemented in
1074          * drm_atomic_helper_commit() together with the nonblocking commit
1075          * helpers (see drm_atomic_helper_setup_commit() for a starting point)
1076          * to implement blocking and nonblocking commits easily. It is not used
1077          * by the atomic helpers
1078          *
1079          * This function is called when the new atomic state has already been
1080          * swapped into the various state pointers. The passed in state
1081          * therefore contains copies of the old/previous state. This hook should
1082          * commit the new state into hardware. Note that the helpers have
1083          * already waited for preceeding atomic commits and fences, but drivers
1084          * can add more waiting calls at the start of their implementation, e.g.
1085          * to wait for driver-internal request for implicit syncing, before
1086          * starting to commit the update to the hardware.
1087          *
1088          * After the atomic update is committed to the hardware this hook needs
1089          * to call drm_atomic_helper_commit_hw_done(). Then wait for the upate
1090          * to be executed by the hardware, for example using
1091          * drm_atomic_helper_wait_for_vblanks(), and then clean up the old
1092          * framebuffers using drm_atomic_helper_cleanup_planes().
1093          *
1094          * When disabling a CRTC this hook _must_ stall for the commit to
1095          * complete. Vblank waits don't work on disabled CRTC, hence the core
1096          * can't take care of this. And it also can't rely on the vblank event,
1097          * since that can be signalled already when the screen shows black,
1098          * which can happen much earlier than the last hardware access needed to
1099          * shut off the display pipeline completely.
1100          *
1101          * This hook is optional, the default implementation is
1102          * drm_atomic_helper_commit_tail().
1103          */
1104         void (*atomic_commit_tail)(struct drm_atomic_state *state);
1105 };
1106
1107 #endif