src/gbm/main/gbm.c

   1 /*
   2  * Copyright © 2011 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  18  * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  19  * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  20  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  22  * DEALINGS IN THE SOFTWARE.
  23  *
  24  * Authors:
  25  *    Benjamin Franzke <benjaminfranzke@googlemail.com>
  26  */
  27
  28 #include <stddef.h>
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <stdint.h>
  33
  34 #ifdef MAJOR_IN_MKDEV
  35 #include <sys/mkdev.h>
  36 #endif
  37 #ifdef MAJOR_IN_SYSMACROS
  38 #include <sys/sysmacros.h>
  39 #endif
  40 #include <sys/stat.h>
  41 #include <unistd.h>
  42 #include <errno.h>
  43
  44 #include "gbm.h"
  45 #include "gbmint.h"
  46 #include "backend.h"
  47
  48 /** Returns the file description for the gbm device
  49  *
  50  * \return The fd that the struct gbm_device was created with
  51  */
  52 GBM_EXPORT int
  53 gbm_device_get_fd(struct gbm_device *gbm)
  54 {
  55    return gbm->fd;
  56 }
  57
  58 /** Get the backend name for the given gbm device
  59  *
  60  * \return The backend name string - this belongs to the device and must not
  61  * be freed
  62  */
  63 GBM_EXPORT const char *
  64 gbm_device_get_backend_name(struct gbm_device *gbm)
  65 {
  66    return gbm->name;
  67 }
  68
  69 /** Test if a format is supported for a given set of usage flags.
  70  *
  71  * \param gbm The created buffer manager
  72  * \param format The format to test
  73  * \param usage A bitmask of the usages to test the format against
  74  * \return 1 if the format is supported otherwise 0
  75  *
  76  * \sa enum gbm_bo_flags for the list of flags that the format can be
  77  * tested against
  78  *
  79  * \sa enum gbm_bo_format for the list of formats
  80  */
  81 GBM_EXPORT int
  82 gbm_device_is_format_supported(struct gbm_device *gbm,
  83                                uint32_t format, uint32_t usage)
  84 {
  85    return gbm->is_format_supported(gbm, format, usage);
  86 }
  87
  88 /** Get the number of planes that are required for a given format+modifier
  89  *
  90  * \param gbm The gbm device returned from gbm_create_device()
  91  * \param format The format to query
  92  * \param modifier The modifier to query
  93  */
  94 GBM_EXPORT int
  95 gbm_device_get_format_modifier_plane_count(struct gbm_device *gbm,
  96                                            uint32_t format,
  97                                            uint64_t modifier)
  98 {
  99    return gbm->get_format_modifier_plane_count(gbm, format, modifier);
 100 }
 101
 102 /** Destroy the gbm device and free all resources associated with it.
 103  *
 104  * \param gbm The device created using gbm_create_device()
 105  */
 106 GBM_EXPORT void
 107 gbm_device_destroy(struct gbm_device *gbm)
 108 {
 109    gbm->refcount--;
 110    if (gbm->refcount == 0)
 111       gbm->destroy(gbm);
 112 }
 113
 114 /** Create a gbm device for allocating buffers
 115  *
 116  * The file descriptor passed in is used by the backend to communicate with
 117  * platform for allocating the memory. For allocations using DRI this would be
 118  * the file descriptor returned when opening a device such as \c
 119  * /dev/dri/card0
 120  *
 121  * \param fd The file descriptor for a backend specific device
 122  * \return The newly created struct gbm_device. The resources associated with
 123  * the device should be freed with gbm_device_destroy() when it is no longer
 124  * needed. If the creation of the device failed NULL will be returned.
 125  */
 126 GBM_EXPORT struct gbm_device *
 127 gbm_create_device(int fd)
 128 {
 129    struct gbm_device *gbm = NULL;
 130    struct stat buf;
 131
 132    if (fd < 0 || fstat(fd, &buf) < 0 || !S_ISCHR(buf.st_mode)) {
 133       errno = EINVAL;
 134       return NULL;
 135    }
 136
 137    gbm = _gbm_create_device(fd);
 138    if (gbm == NULL)
 139       return NULL;
 140
 141    gbm->dummy = gbm_create_device;
 142    gbm->stat = buf;
 143    gbm->refcount = 1;
 144
 145    return gbm;
 146 }
 147
 148 /** Get the width of the buffer object
 149  *
 150  * \param bo The buffer object
 151  * \return The width of the allocated buffer object
 152  *
 153  */
 154 GBM_EXPORT uint32_t
 155 gbm_bo_get_width(struct gbm_bo *bo)
 156 {
 157    return bo->width;
 158 }
 159
 160 /** Get the height of the buffer object
 161  *
 162  * \param bo The buffer object
 163  * \return The height of the allocated buffer object
 164  */
 165 GBM_EXPORT uint32_t
 166 gbm_bo_get_height(struct gbm_bo *bo)
 167 {
 168    return bo->height;
 169 }
 170
 171 /** Get the stride of the buffer object
 172  *
 173  * This is calculated by the backend when it does the allocation in
 174  * gbm_bo_create()
 175  *
 176  * \param bo The buffer object
 177  * \return The stride of the allocated buffer object in bytes
 178  */
 179 GBM_EXPORT uint32_t
 180 gbm_bo_get_stride(struct gbm_bo *bo)
 181 {
 182    return gbm_bo_get_stride_for_plane(bo, 0);
 183 }
 184
 185 /** Get the stride for the given plane
 186  *
 187  * \param bo The buffer object
 188  * \param plane for which you want the stride
 189  *
 190  * \sa gbm_bo_get_stride()
 191  */
 192 GBM_EXPORT uint32_t
 193 gbm_bo_get_stride_for_plane(struct gbm_bo *bo, int plane)
 194 {
 195    return bo->gbm->bo_get_stride(bo, plane);
 196 }
 197
 198 /** Get the format of the buffer object
 199  *
 200  * The format of the pixels in the buffer.
 201  *
 202  * \param bo The buffer object
 203  * \return The format of buffer object, one of the GBM_FORMAT_* codes
 204  */
 205 GBM_EXPORT uint32_t
 206 gbm_bo_get_format(struct gbm_bo *bo)
 207 {
 208    return bo->format;
 209 }
 210
 211 /** Get the bit-per-pixel of the buffer object's format
 212  *
 213  * The bits-per-pixel of the buffer object's format.
 214  *
 215  * Note; The 'in-memory pixel' concept makes no sense for YUV formats
 216  * (pixels are the result of the combination of multiple memory sources:
 217  * Y, Cb & Cr; usually these are even in separate buffers), so YUV
 218  * formats are not supported by this function.
 219  *
 220  * \param bo The buffer object
 221  * \return The number of bits0per-pixel of the buffer object's format.
 222  */
 223 GBM_EXPORT uint32_t
 224 gbm_bo_get_bpp(struct gbm_bo *bo)
 225 {
 226    switch (bo->format) {
 227       default:
 228          return 0;
 229       case GBM_FORMAT_C8:
 230       case GBM_FORMAT_R8:
 231       case GBM_FORMAT_RGB332:
 232       case GBM_FORMAT_BGR233:
 233          return 8;
 234       case GBM_FORMAT_GR88:
 235       case GBM_FORMAT_XRGB4444:
 236       case GBM_FORMAT_XBGR4444:
 237       case GBM_FORMAT_RGBX4444:
 238       case GBM_FORMAT_BGRX4444:
 239       case GBM_FORMAT_ARGB4444:
 240       case GBM_FORMAT_ABGR4444:
 241       case GBM_FORMAT_RGBA4444:
 242       case GBM_FORMAT_BGRA4444:
 243       case GBM_FORMAT_XRGB1555:
 244       case GBM_FORMAT_XBGR1555:
 245       case GBM_FORMAT_RGBX5551:
 246       case GBM_FORMAT_BGRX5551:
 247       case GBM_FORMAT_ARGB1555:
 248       case GBM_FORMAT_ABGR1555:
 249       case GBM_FORMAT_RGBA5551:
 250       case GBM_FORMAT_BGRA5551:
 251       case GBM_FORMAT_RGB565:
 252       case GBM_FORMAT_BGR565:
 253          return 16;
 254       case GBM_FORMAT_RGB888:
 255       case GBM_FORMAT_BGR888:
 256          return 24;
 257       case GBM_FORMAT_XRGB8888:
 258       case GBM_FORMAT_XBGR8888:
 259       case GBM_FORMAT_RGBX8888:
 260       case GBM_FORMAT_BGRX8888:
 261       case GBM_FORMAT_ARGB8888:
 262       case GBM_FORMAT_ABGR8888:
 263       case GBM_FORMAT_RGBA8888:
 264       case GBM_FORMAT_BGRA8888:
 265       case GBM_FORMAT_XRGB2101010:
 266       case GBM_FORMAT_XBGR2101010:
 267       case GBM_FORMAT_RGBX1010102:
 268       case GBM_FORMAT_BGRX1010102:
 269       case GBM_FORMAT_ARGB2101010:
 270       case GBM_FORMAT_ABGR2101010:
 271       case GBM_FORMAT_RGBA1010102:
 272       case GBM_FORMAT_BGRA1010102:
 273          return 32;
 274    }
 275 }
 276
 277 /** Get the offset for the data of the specified plane
 278  *
 279  * Extra planes, and even the first plane, may have an offset from the start of
 280  * the buffer object. This function will provide the offset for the given plane
 281  * to be used in various KMS APIs.
 282  *
 283  * \param bo The buffer object
 284  * \return The offset
 285  */
 286 GBM_EXPORT uint32_t
 287 gbm_bo_get_offset(struct gbm_bo *bo, int plane)
 288 {
 289    return bo->gbm->bo_get_offset(bo, plane);
 290 }
 291
 292 /** Get the gbm device used to create the buffer object
 293  *
 294  * \param bo The buffer object
 295  * \return Returns the gbm device with which the buffer object was created
 296  */
 297 GBM_EXPORT struct gbm_device *
 298 gbm_bo_get_device(struct gbm_bo *bo)
 299 {
 300         return bo->gbm;
 301 }
 302
 303 /** Get the handle of the buffer object
 304  *
 305  * This is stored in the platform generic union gbm_bo_handle type. However
 306  * the format of this handle is platform specific.
 307  *
 308  * \param bo The buffer object
 309  * \return Returns the handle of the allocated buffer object
 310  */
 311 GBM_EXPORT union gbm_bo_handle
 312 gbm_bo_get_handle(struct gbm_bo *bo)
 313 {
 314    return bo->handle;
 315 }
 316
 317 /** Get a DMA-BUF file descriptor for the buffer object
 318  *
 319  * This function creates a DMA-BUF (also known as PRIME) file descriptor
 320  * handle for the buffer object.  Each call to gbm_bo_get_fd() returns a new
 321  * file descriptor and the caller is responsible for closing the file
 322  * descriptor.
 323
 324  * \param bo The buffer object
 325  * \return Returns a file descriptor referring to the underlying buffer or -1
 326  * if an error occurs.
 327  */
 328 GBM_EXPORT int
 329 gbm_bo_get_fd(struct gbm_bo *bo)
 330 {
 331    return bo->gbm->bo_get_fd(bo);
 332 }
 333
 334 /** Get the number of planes for the given bo.
 335  *
 336  * \param bo The buffer object
 337  * \return The number of planes
 338  */
 339 GBM_EXPORT int
 340 gbm_bo_get_plane_count(struct gbm_bo *bo)
 341 {
 342    return bo->gbm->bo_get_planes(bo);
 343 }
 344
 345 /** Get the handle for the specified plane of the buffer object
 346  *
 347  * This function gets the handle for any plane associated with the BO. When
 348  * dealing with multi-planar formats, or formats which might have implicit
 349  * planes based on different underlying hardware it is necessary for the client
 350  * to be able to get this information to pass to the DRM.
 351  *
 352  * \param bo The buffer object
 353  * \param plane the plane to get a handle for
 354  *
 355  * \sa gbm_bo_get_handle()
 356  */
 357 GBM_EXPORT union gbm_bo_handle
 358 gbm_bo_get_handle_for_plane(struct gbm_bo *bo, int plane)
 359 {
 360    return bo->gbm->bo_get_handle(bo, plane);
 361 }
 362
 363 /**
 364  * Get the chosen modifier for the buffer object
 365  *
 366  * This function returns the modifier that was chosen for the object. These
 367  * properties may be generic, or platform/implementation dependent.
 368  *
 369  * \param bo The buffer object
 370  * \return Returns the selected modifier (chosen by the implementation) for the
 371  * BO.
 372  * \sa gbm_bo_create_with_modifiers() where possible modifiers are set
 373  * \sa gbm_surface_create_with_modifiers() where possible modifiers are set
 374  * \sa define DRM_FORMAT_MOD_* in drm_fourcc.h for possible modifiers
 375  */
 376 GBM_EXPORT uint64_t
 377 gbm_bo_get_modifier(struct gbm_bo *bo)
 378 {
 379    return bo->gbm->bo_get_modifier(bo);
 380 }
 381
 382 /** Write data into the buffer object
 383  *
 384  * If the buffer object was created with the GBM_BO_USE_WRITE flag,
 385  * this function can be used to write data into the buffer object.  The
 386  * data is copied directly into the object and it's the responsibility
 387  * of the caller to make sure the data represents valid pixel data,
 388  * according to the width, height, stride and format of the buffer object.
 389  *
 390  * \param bo The buffer object
 391  * \param buf The data to write
 392  * \param count The number of bytes to write
 393  * \return Returns 0 on success, otherwise -1 is returned an errno set
 394  */
 395 GBM_EXPORT int
 396 gbm_bo_write(struct gbm_bo *bo, const void *buf, size_t count)
 397 {
 398    return bo->gbm->bo_write(bo, buf, count);
 399 }
 400
 401 /** Set the user data associated with a buffer object
 402  *
 403  * \param bo The buffer object
 404  * \param data The data to associate to the buffer object
 405  * \param destroy_user_data A callback (which may be %NULL) that will be
 406  * called prior to the buffer destruction
 407  */
 408 GBM_EXPORT void
 409 gbm_bo_set_user_data(struct gbm_bo *bo, void *data,
 410                      void (*destroy_user_data)(struct gbm_bo *, void *))
 411 {
 412    bo->user_data = data;
 413    bo->destroy_user_data = destroy_user_data;
 414 }
 415
 416 /** Get the user data associated with a buffer object
 417  *
 418  * \param bo The buffer object
 419  * \return Returns the user data associated with the buffer object or %NULL
 420  * if no data was associated with it
 421  *
 422  * \sa gbm_bo_set_user_data()
 423  */
 424 GBM_EXPORT void *
 425 gbm_bo_get_user_data(struct gbm_bo *bo)
 426 {
 427    return bo->user_data;
 428 }
 429
 430 /**
 431  * Destroys the given buffer object and frees all resources associated with
 432  * it.
 433  *
 434  * \param bo The buffer object
 435  */
 436 GBM_EXPORT void
 437 gbm_bo_destroy(struct gbm_bo *bo)
 438 {
 439    if (bo->destroy_user_data)
 440       bo->destroy_user_data(bo, bo->user_data);
 441
 442    bo->gbm->bo_destroy(bo);
 443 }
 444
 445 /**
 446  * Allocate a buffer object for the given dimensions
 447  *
 448  * \param gbm The gbm device returned from gbm_create_device()
 449  * \param width The width for the buffer
 450  * \param height The height for the buffer
 451  * \param format The format to use for the buffer, from GBM_FORMAT_* or
 452  * GBM_BO_FORMAT_* tokens
 453  * \param usage The union of the usage flags for this buffer
 454  *
 455  * \return A newly allocated buffer that should be freed with gbm_bo_destroy()
 456  * when no longer needed. If an error occurs during allocation %NULL will be
 457  * returned and errno set.
 458  *
 459  * \sa enum gbm_bo_flags for the list of usage flags
 460  */
 461 GBM_EXPORT struct gbm_bo *
 462 gbm_bo_create(struct gbm_device *gbm,
 463               uint32_t width, uint32_t height,
 464               uint32_t format, uint32_t usage)
 465 {
 466    if (width == 0 || height == 0) {
 467       errno = EINVAL;
 468       return NULL;
 469    }
 470
 471    return gbm->bo_create(gbm, width, height, format, usage, NULL, 0);
 472 }
 473
 474 GBM_EXPORT struct gbm_bo *
 475 gbm_bo_create_with_modifiers(struct gbm_device *gbm,
 476                              uint32_t width, uint32_t height,
 477                              uint32_t format,
 478                              const uint64_t *modifiers,
 479                              const unsigned int count)
 480 {
 481    if (width == 0 || height == 0) {
 482       errno = EINVAL;
 483       return NULL;
 484    }
 485
 486    if ((count && !modifiers) || (modifiers && !count)) {
 487       errno = EINVAL;
 488       return NULL;
 489    }
 490
 491    return gbm->bo_create(gbm, width, height, format, 0, modifiers, count);
 492 }
 493 /**
 494  * Create a gbm buffer object from an foreign object
 495  *
 496  * This function imports a foreign object and creates a new gbm bo for it.
 497  * This enabled using the foreign object with a display API such as KMS.
 498  * Currently three types of foreign objects are supported, indicated by the type
 499  * argument:
 500  *
 501  *   GBM_BO_IMPORT_WL_BUFFER
 502  *   GBM_BO_IMPORT_EGL_IMAGE
 503  *   GBM_BO_IMPORT_FD
 504  *
 505  * The gbm bo shares the underlying pixels but its life-time is
 506  * independent of the foreign object.
 507  *
 508  * \param gbm The gbm device returned from gbm_create_device()
 509  * \param type The type of object we're importing
 510  * \param buffer Pointer to the external object
 511  * \param usage The union of the usage flags for this buffer
 512  *
 513  * \return A newly allocated buffer object that should be freed with
 514  * gbm_bo_destroy() when no longer needed. On error, %NULL is returned
 515  * and errno is set.
 516  *
 517  * \sa enum gbm_bo_flags for the list of usage flags
 518  */
 519 GBM_EXPORT struct gbm_bo *
 520 gbm_bo_import(struct gbm_device *gbm,
 521               uint32_t type, void *buffer, uint32_t usage)
 522 {
 523    return gbm->bo_import(gbm, type, buffer, usage);
 524 }
 525
 526 /**
 527  * Map a region of a gbm buffer object for cpu access
 528  *
 529  * This function maps a region of a gbm bo for cpu read and/or write
 530  * access.
 531  *
 532  * \param bo The buffer object
 533  * \param x The X (top left origin) starting position of the mapped region for
 534  * the buffer
 535  * \param y The Y (top left origin) starting position of the mapped region for
 536  * the buffer
 537  * \param width The width of the mapped region for the buffer
 538  * \param height The height of the mapped region for the buffer
 539  * \param flags The union of the GBM_BO_TRANSFER_* flags for this buffer
 540  * \param stride Ptr for returned stride in bytes of the mapped region
 541  * \param map_data Returned opaque ptr for the mapped region
 542  *
 543  * \return Address of the mapped buffer that should be unmapped with
 544  * gbm_bo_unmap() when no longer needed. On error, %NULL is returned
 545  * and errno is set.
 546  *
 547  * \sa enum gbm_bo_transfer_flags for the list of flags
 548  */
 549 GBM_EXPORT void *
 550 gbm_bo_map(struct gbm_bo *bo,
 551               uint32_t x, uint32_t y,
 552               uint32_t width, uint32_t height,
 553               uint32_t flags, uint32_t *stride, void **map_data)
 554 {
 555    if (!bo || width == 0 || height == 0 || !stride || !map_data) {
 556       errno = EINVAL;
 557       return NULL;
 558    }
 559
 560    return bo->gbm->bo_map(bo, x, y, width, height,
 561                           flags, stride, map_data);
 562 }
 563
 564 /**
 565  * Unmap a previously mapped region of a gbm buffer object
 566  *
 567  * This function unmaps a region of a gbm bo for cpu read and/or write
 568  * access.
 569  *
 570  * \param bo The buffer object
 571  * \param map_data opaque ptr returned from prior gbm_bo_map
 572  */
 573 GBM_EXPORT void
 574 gbm_bo_unmap(struct gbm_bo *bo, void *map_data)
 575 {
 576    bo->gbm->bo_unmap(bo, map_data);
 577 }
 578
 579 /**
 580  * Allocate a surface object
 581  *
 582  * \param gbm The gbm device returned from gbm_create_device()
 583  * \param width The width for the surface
 584  * \param height The height for the surface
 585  * \param format The format to use for the surface
 586  *
 587  * \return A newly allocated surface that should be freed with
 588  * gbm_surface_destroy() when no longer needed. If an error occurs
 589  * during allocation %NULL will be returned.
 590  *
 591  * \sa enum gbm_bo_format for the list of formats
 592  */
 593 GBM_EXPORT struct gbm_surface *
 594 gbm_surface_create(struct gbm_device *gbm,
 595                    uint32_t width, uint32_t height,
 596                    uint32_t format, uint32_t flags)
 597 {
 598    return gbm->surface_create(gbm, width, height, format, flags, NULL, 0);
 599 }
 600
 601 GBM_EXPORT struct gbm_surface *
 602 gbm_surface_create_with_modifiers(struct gbm_device *gbm,
 603                                   uint32_t width, uint32_t height,
 604                                   uint32_t format,
 605                                   const uint64_t *modifiers,
 606                                   const unsigned int count)
 607 {
 608    if ((count && !modifiers) || (modifiers && !count)) {
 609       errno = EINVAL;
 610       return NULL;
 611    }
 612
 613    return gbm->surface_create(gbm, width, height, format, 0,
 614                               modifiers, count);
 615 }
 616
 617 /**
 618  * Destroys the given surface and frees all resources associated with
 619  * it.
 620  *
 621  * All buffers locked with gbm_surface_lock_front_buffer() should be
 622  * released prior to calling this function.
 623  *
 624  * \param surf The surface
 625  */
 626 GBM_EXPORT void
 627 gbm_surface_destroy(struct gbm_surface *surf)
 628 {
 629    surf->gbm->surface_destroy(surf);
 630 }
 631
 632 /**
 633  * Lock the surface's current front buffer
 634  *
 635  * Lock rendering to the surface's current front buffer until it is
 636  * released with gbm_surface_release_buffer().
 637  *
 638  * This function must be called exactly once after calling
 639  * eglSwapBuffers.  Calling it before any eglSwapBuffer has happened
 640  * on the surface or two or more times after eglSwapBuffers is an
 641  * error.  A new bo representing the new front buffer is returned.  On
 642  * multiple invocations, all the returned bos must be released in
 643  * order to release the actual surface buffer.
 644  *
 645  * \param surf The surface
 646  *
 647  * \return A buffer object that should be released with
 648  * gbm_surface_release_buffer() when no longer needed.  The implementation
 649  * is free to reuse buffers released with gbm_surface_release_buffer() so
 650  * this bo should not be destroyed using gbm_bo_destroy().  If an error
 651  * occurs this function returns %NULL.
 652  */
 653 GBM_EXPORT struct gbm_bo *
 654 gbm_surface_lock_front_buffer(struct gbm_surface *surf)
 655 {
 656    return surf->gbm->surface_lock_front_buffer(surf);
 657 }
 658
 659 /**
 660  * Release a locked buffer obtained with gbm_surface_lock_front_buffer()
 661  *
 662  * Returns the underlying buffer to the gbm surface.  Releasing a bo
 663  * will typically make gbm_surface_has_free_buffer() return 1 and thus
 664  * allow rendering the next frame, but not always. The implementation
 665  * may choose to destroy the bo immediately or reuse it, in which case
 666  * the user data associated with it is unchanged.
 667  *
 668  * \param surf The surface
 669  * \param bo The buffer object
 670  */
 671 GBM_EXPORT void
 672 gbm_surface_release_buffer(struct gbm_surface *surf, struct gbm_bo *bo)
 673 {
 674    surf->gbm->surface_release_buffer(surf, bo);
 675 }
 676
 677 /**
 678  * Return whether or not a surface has free (non-locked) buffers
 679  *
 680  * Before starting a new frame, the surface must have a buffer
 681  * available for rendering.  Initially, a gbm surface will have a free
 682  * buffer, but after one or more buffers have been locked (\sa
 683  * gbm_surface_lock_front_buffer()), the application must check for a
 684  * free buffer before rendering.
 685  *
 686  * If a surface doesn't have a free buffer, the application must
 687  * return a buffer to the surface using gbm_surface_release_buffer()
 688  * and after that, the application can query for free buffers again.
 689  *
 690  * \param surf The surface
 691  * \return 1 if the surface has free buffers, 0 otherwise
 692  */
 693 GBM_EXPORT int
 694 gbm_surface_has_free_buffers(struct gbm_surface *surf)
 695 {
 696    return surf->gbm->surface_has_free_buffers(surf);
 697 }
 698
 699 /* The two GBM_BO_FORMAT_[XA]RGB8888 formats alias the GBM_FORMAT_*
 700  * formats of the same name. We want to accept them whenever someone
 701  * has a GBM format, but never return them to the user. */
 702 uint32_t
 703 gbm_format_canonicalize(uint32_t gbm_format)
 704 {
 705    switch (gbm_format) {
 706    case GBM_BO_FORMAT_XRGB8888:
 707       return GBM_FORMAT_XRGB8888;
 708    case GBM_BO_FORMAT_ARGB8888:
 709       return GBM_FORMAT_ARGB8888;
 710    default:
 711       return gbm_format;
 712    }
 713 }
 714
 715 /**
 716  * Returns a string representing the fourcc format name.
 717  *
 718  * \param desc Caller-provided storage for the format name string.
 719  * \return String containing the fourcc of the format.
 720  */
 721 GBM_EXPORT char *
 722 gbm_format_get_name(uint32_t gbm_format, struct gbm_format_name_desc *desc)
 723 {
 724    gbm_format = gbm_format_canonicalize(gbm_format);
 725
 726    desc->name[0] = gbm_format;
 727    desc->name[1] = gbm_format >> 8;
 728    desc->name[2] = gbm_format >> 16;
 729    desc->name[3] = gbm_format >> 24;
 730    desc->name[4] = 0;
 731
 732    return desc->name;
 733 }