summaryrefslogtreecommitdiffstats
path: root/src/glx/dri_common.c
blob: 0f8f7134b4ad0b03c90ba3084c78bb51f4df9a3d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
/*
 * Copyright 1998-1999 Precision Insight, Inc., Cedar Park, Texas.
 * Copyright © 2008 Red Hat, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Soft-
 * ware"), to deal in the Software without restriction, including without
 * limitation the rights to use, copy, modify, merge, publish, distribute,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, provided that the above copyright
 * notice(s) and this permission notice appear in all copies of the Soft-
 * ware and that both the above copyright notice(s) and this permission
 * notice appear in supporting documentation.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABIL-
 * ITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY
 * RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS INCLUDED IN
 * THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT OR CONSE-
 * QUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFOR-
 * MANCE OF THIS SOFTWARE.
 *
 * Except as contained in this notice, the name of a copyright holder shall
 * not be used in advertising or otherwise to promote the sale, use or
 * other dealings in this Software without prior written authorization of
 * the copyright holder.
 *
 * Authors:
 *   Kevin E. Martin <kevin@precisioninsight.com>
 *   Brian Paul <brian@precisioninsight.com>
 *   Kristian Høgsberg (krh@redhat.com)
 */

#if defined(GLX_DIRECT_RENDERING) && !defined(GLX_USE_APPLEGL)

#include <unistd.h>
#include <dlfcn.h>
#include <stdarg.h>
#include "glxclient.h"
#include "dri_common.h"
#include "loader.h"

#ifndef RTLD_NOW
#define RTLD_NOW 0
#endif
#ifndef RTLD_GLOBAL
#define RTLD_GLOBAL 0
#endif

_X_HIDDEN void
dri_message(int level, const char *f, ...)
{
   va_list args;
   int threshold = _LOADER_WARNING;
   const char *libgl_debug;

   libgl_debug = getenv("LIBGL_DEBUG");
   if (libgl_debug) {
      if (strstr(libgl_debug, "quiet"))
         threshold = _LOADER_FATAL;
      else if (strstr(libgl_debug, "verbose"))
         threshold = _LOADER_DEBUG;
   }

   /* Note that the _LOADER_* levels are lower numbers for more severe. */
   if (level <= threshold) {
      fprintf(stderr, "libGL%s: ", level <= _LOADER_WARNING ? " error" : "");
      va_start(args, f);
      vfprintf(stderr, f, args);
      va_end(args);
   }
}

#ifndef GL_LIB_NAME
#define GL_LIB_NAME "libGL.so.1"
#endif

#ifndef DEFAULT_DRIVER_DIR
/* this is normally defined in Mesa/configs/default with DRI_DRIVER_SEARCH_PATH */
#define DEFAULT_DRIVER_DIR "/usr/local/lib/dri"
#endif

/**
 * Try to \c dlopen the named driver.
 *
 * This function adds the "_dri.so" suffix to the driver name and searches the
 * directories specified by the \c LIBGL_DRIVERS_PATH environment variable in
 * order to find the driver.
 *
 * \param driverName - a name like "i965", "radeon", "nouveau", etc.
 *
 * \returns
 * A handle from \c dlopen, or \c NULL if driver file not found.
 */
_X_HIDDEN void *
driOpenDriver(const char *driverName)
{
   void *glhandle, *handle;
   const char *libPaths, *p, *next;
   char realDriverName[200];
   int len;

   /* Attempt to make sure libGL symbols will be visible to the driver */
   glhandle = dlopen(GL_LIB_NAME, RTLD_NOW | RTLD_GLOBAL);

   libPaths = NULL;
   if (geteuid() == getuid()) {
      /* don't allow setuid apps to use LIBGL_DRIVERS_PATH */
      libPaths = getenv("LIBGL_DRIVERS_PATH");
      if (!libPaths)
         libPaths = getenv("LIBGL_DRIVERS_DIR");        /* deprecated */
   }
   if (libPaths == NULL)
      libPaths = DEFAULT_DRIVER_DIR;

   handle = NULL;
   for (p = libPaths; *p; p = next) {
      next = strchr(p, ':');
      if (next == NULL) {
         len = strlen(p);
         next = p + len;
      }
      else {
         len = next - p;
         next++;
      }

#ifdef GLX_USE_TLS
      snprintf(realDriverName, sizeof realDriverName,
               "%.*s/tls/%s_dri.so", len, p, driverName);
      InfoMessageF("OpenDriver: trying %s\n", realDriverName);
      handle = dlopen(realDriverName, RTLD_NOW | RTLD_GLOBAL);
#endif

      if (handle == NULL) {
         snprintf(realDriverName, sizeof realDriverName,
                  "%.*s/%s_dri.so", len, p, driverName);
         InfoMessageF("OpenDriver: trying %s\n", realDriverName);
         handle = dlopen(realDriverName, RTLD_NOW | RTLD_GLOBAL);
      }

      if (handle != NULL)
         break;
      else
         InfoMessageF("dlopen %s failed (%s)\n", realDriverName, dlerror());
   }

   if (!handle)
      ErrorMessageF("unable to load driver: %s_dri.so\n", driverName);

   if (glhandle)
      dlclose(glhandle);

   return handle;
}

_X_HIDDEN const __DRIextension **
driGetDriverExtensions(void *handle, const char *driver_name)
{
   const __DRIextension **extensions = NULL;
   const __DRIextension **(*get_extensions)(void);
   char *get_extensions_name = loader_get_extensions_name(driver_name);

   if (get_extensions_name) {
      get_extensions = dlsym(handle, get_extensions_name);
      if (get_extensions) {
         free(get_extensions_name);
         return get_extensions();
      } else {
         InfoMessageF("driver does not expose %s(): %s\n",
                      get_extensions_name, dlerror());
         free(get_extensions_name);
      }
   }

   extensions = dlsym(handle, __DRI_DRIVER_EXTENSIONS);
   if (extensions == NULL) {
      ErrorMessageF("driver exports no extensions (%s)\n", dlerror());
      return NULL;
   }

   return extensions;
}

static GLboolean
__driGetMSCRate(__DRIdrawable *draw,
		int32_t * numerator, int32_t * denominator,
		void *loaderPrivate)
{
   __GLXDRIdrawable *glxDraw = loaderPrivate;

   return __glxGetMscRate(glxDraw->psc, numerator, denominator);
}

_X_HIDDEN const __DRIsystemTimeExtension systemTimeExtension = {
   .base = {__DRI_SYSTEM_TIME, 1 },

   .getUST              = __glXGetUST,
   .getMSCRate          = __driGetMSCRate
};

#define __ATTRIB(attrib, field) \
    { attrib, offsetof(struct glx_config, field) }

static const struct
{
   unsigned int attrib, offset;
} attribMap[] = {
   __ATTRIB(__DRI_ATTRIB_BUFFER_SIZE, rgbBits),
      __ATTRIB(__DRI_ATTRIB_LEVEL, level),
      __ATTRIB(__DRI_ATTRIB_RED_SIZE, redBits),
      __ATTRIB(__DRI_ATTRIB_GREEN_SIZE, greenBits),
      __ATTRIB(__DRI_ATTRIB_BLUE_SIZE, blueBits),
      __ATTRIB(__DRI_ATTRIB_ALPHA_SIZE, alphaBits),
      __ATTRIB(__DRI_ATTRIB_DEPTH_SIZE, depthBits),
      __ATTRIB(__DRI_ATTRIB_STENCIL_SIZE, stencilBits),
      __ATTRIB(__DRI_ATTRIB_ACCUM_RED_SIZE, accumRedBits),
      __ATTRIB(__DRI_ATTRIB_ACCUM_GREEN_SIZE, accumGreenBits),
      __ATTRIB(__DRI_ATTRIB_ACCUM_BLUE_SIZE, accumBlueBits),
      __ATTRIB(__DRI_ATTRIB_ACCUM_ALPHA_SIZE, accumAlphaBits),
      __ATTRIB(__DRI_ATTRIB_SAMPLE_BUFFERS, sampleBuffers),
      __ATTRIB(__DRI_ATTRIB_SAMPLES, samples),
      __ATTRIB(__DRI_ATTRIB_DOUBLE_BUFFER, doubleBufferMode),
      __ATTRIB(__DRI_ATTRIB_STEREO, stereoMode),
      __ATTRIB(__DRI_ATTRIB_AUX_BUFFERS, numAuxBuffers),
#if 0
      __ATTRIB(__DRI_ATTRIB_TRANSPARENT_TYPE, transparentPixel),
      __ATTRIB(__DRI_ATTRIB_TRANSPARENT_INDEX_VALUE, transparentIndex),
      __ATTRIB(__DRI_ATTRIB_TRANSPARENT_RED_VALUE, transparentRed),
      __ATTRIB(__DRI_ATTRIB_TRANSPARENT_GREEN_VALUE, transparentGreen),
      __ATTRIB(__DRI_ATTRIB_TRANSPARENT_BLUE_VALUE, transparentBlue),
      __ATTRIB(__DRI_ATTRIB_TRANSPARENT_ALPHA_VALUE, transparentAlpha),
      __ATTRIB(__DRI_ATTRIB_RED_MASK, redMask),
      __ATTRIB(__DRI_ATTRIB_GREEN_MASK, greenMask),
      __ATTRIB(__DRI_ATTRIB_BLUE_MASK, blueMask),
      __ATTRIB(__DRI_ATTRIB_ALPHA_MASK, alphaMask),
#endif
      __ATTRIB(__DRI_ATTRIB_MAX_PBUFFER_WIDTH, maxPbufferWidth),
      __ATTRIB(__DRI_ATTRIB_MAX_PBUFFER_HEIGHT, maxPbufferHeight),
      __ATTRIB(__DRI_ATTRIB_MAX_PBUFFER_PIXELS, maxPbufferPixels),
      __ATTRIB(__DRI_ATTRIB_OPTIMAL_PBUFFER_WIDTH, optimalPbufferWidth),
      __ATTRIB(__DRI_ATTRIB_OPTIMAL_PBUFFER_HEIGHT, optimalPbufferHeight),
      __ATTRIB(__DRI_ATTRIB_SWAP_METHOD, swapMethod),
      __ATTRIB(__DRI_ATTRIB_BIND_TO_TEXTURE_RGB, bindToTextureRgb),
      __ATTRIB(__DRI_ATTRIB_BIND_TO_TEXTURE_RGBA, bindToTextureRgba),
      __ATTRIB(__DRI_ATTRIB_BIND_TO_MIPMAP_TEXTURE,
                     bindToMipmapTexture),
      __ATTRIB(__DRI_ATTRIB_YINVERTED, yInverted),
      __ATTRIB(__DRI_ATTRIB_FRAMEBUFFER_SRGB_CAPABLE, sRGBCapable)
};

static int
scalarEqual(struct glx_config *mode, unsigned int attrib, unsigned int value)
{
   unsigned glxValue, i;

   for (i = 0; i < ARRAY_SIZE(attribMap); i++)
      if (attribMap[i].attrib == attrib) {
         glxValue = *(unsigned int *) ((char *) mode + attribMap[i].offset);
         return glxValue == GLX_DONT_CARE || glxValue == value;
      }

   return GL_TRUE;              /* Is a non-existing attribute equal to value? */
}

static int
driConfigEqual(const __DRIcoreExtension *core,
               struct glx_config *config, const __DRIconfig *driConfig)
{
   unsigned int attrib, value, glxValue;
   int i;

   i = 0;
   while (core->indexConfigAttrib(driConfig, i++, &attrib, &value)) {
      switch (attrib) {
      case __DRI_ATTRIB_RENDER_TYPE:
         glxValue = 0;
         if (value & __DRI_ATTRIB_RGBA_BIT) {
            glxValue |= GLX_RGBA_BIT;
         }
         if (value & __DRI_ATTRIB_COLOR_INDEX_BIT) {
            glxValue |= GLX_COLOR_INDEX_BIT;
         }
         if (value & __DRI_ATTRIB_FLOAT_BIT) {
            glxValue |= GLX_RGBA_FLOAT_BIT_ARB;
         }
         if (value & __DRI_ATTRIB_UNSIGNED_FLOAT_BIT) {
            glxValue |= GLX_RGBA_UNSIGNED_FLOAT_BIT_EXT;
         }
         if (glxValue != config->renderType)
            return GL_FALSE;
         break;

      case __DRI_ATTRIB_CONFIG_CAVEAT:
         if (value & __DRI_ATTRIB_NON_CONFORMANT_CONFIG)
            glxValue = GLX_NON_CONFORMANT_CONFIG;
         else if (value & __DRI_ATTRIB_SLOW_BIT)
            glxValue = GLX_SLOW_CONFIG;
         else
            glxValue = GLX_NONE;
         if (glxValue != config->visualRating)
            return GL_FALSE;
         break;

      case __DRI_ATTRIB_BIND_TO_TEXTURE_TARGETS:
         glxValue = 0;
         if (value & __DRI_ATTRIB_TEXTURE_1D_BIT)
            glxValue |= GLX_TEXTURE_1D_BIT_EXT;
         if (value & __DRI_ATTRIB_TEXTURE_2D_BIT)
            glxValue |= GLX_TEXTURE_2D_BIT_EXT;
         if (value & __DRI_ATTRIB_TEXTURE_RECTANGLE_BIT)
            glxValue |= GLX_TEXTURE_RECTANGLE_BIT_EXT;
         if (config->bindToTextureTargets != GLX_DONT_CARE &&
             glxValue != config->bindToTextureTargets)
            return GL_FALSE;
         break;

      default:
         if (!scalarEqual(config, attrib, value))
            return GL_FALSE;
      }
   }

   return GL_TRUE;
}

static struct glx_config *
createDriMode(const __DRIcoreExtension * core,
	      struct glx_config *config, const __DRIconfig **driConfigs)
{
   __GLXDRIconfigPrivate *driConfig;
   int i;

   for (i = 0; driConfigs[i]; i++) {
      if (driConfigEqual(core, config, driConfigs[i]))
         break;
   }

   if (driConfigs[i] == NULL)
      return NULL;

   driConfig = malloc(sizeof *driConfig);
   if (driConfig == NULL)
      return NULL;

   driConfig->base = *config;
   driConfig->driConfig = driConfigs[i];

   return &driConfig->base;
}

_X_HIDDEN struct glx_config *
driConvertConfigs(const __DRIcoreExtension * core,
                  struct glx_config *configs, const __DRIconfig **driConfigs)
{
   struct glx_config head, *tail, *m;

   tail = &head;
   head.next = NULL;
   for (m = configs; m; m = m->next) {
      tail->next = createDriMode(core, m, driConfigs);
      if (tail->next == NULL) {
         /* no matching dri config for m */
         continue;
      }


      tail = tail->next;
   }

   return head.next;
}

_X_HIDDEN void
driDestroyConfigs(const __DRIconfig **configs)
{
   int i;

   for (i = 0; configs[i]; i++)
      free((__DRIconfig *) configs[i]);
   free(configs);
}

_X_HIDDEN __GLXDRIdrawable *
driFetchDrawable(struct glx_context *gc, GLXDrawable glxDrawable)
{
   struct glx_display *const priv = __glXInitialize(gc->psc->dpy);
   __GLXDRIdrawable *pdraw;
   struct glx_screen *psc;

   if (priv == NULL)
      return NULL;

   if (glxDrawable == None)
      return NULL;

   psc = priv->screens[gc->screen];
   if (priv->drawHash == NULL)
      return NULL;

   if (__glxHashLookup(priv->drawHash, glxDrawable, (void *) &pdraw) == 0) {
      pdraw->refcount ++;
      return pdraw;
   }

   pdraw = psc->driScreen->createDrawable(psc, glxDrawable,
                                          glxDrawable, gc->config);

   if (pdraw == NULL) {
      ErrorMessageF("failed to create drawable\n");
      return NULL;
   }

   if (__glxHashInsert(priv->drawHash, glxDrawable, pdraw)) {
      (*pdraw->destroyDrawable) (pdraw);
      return NULL;
   }
   pdraw->refcount = 1;

   return pdraw;
}

_X_HIDDEN void
driReleaseDrawables(struct glx_context *gc)
{
   const struct glx_display *priv = gc->psc->display;
   __GLXDRIdrawable *pdraw;

   if (priv == NULL)
      return;

   if (__glxHashLookup(priv->drawHash,
		       gc->currentDrawable, (void *) &pdraw) == 0) {
      if (pdraw->drawable == pdraw->xDrawable) {
	 pdraw->refcount --;
	 if (pdraw->refcount == 0) {
	    (*pdraw->destroyDrawable)(pdraw);
	    __glxHashDelete(priv->drawHash, gc->currentDrawable);
	 }
      }
   }

   if (__glxHashLookup(priv->drawHash,
		       gc->currentReadable, (void *) &pdraw) == 0) {
      if (pdraw->drawable == pdraw->xDrawable) {
	 pdraw->refcount --;
	 if (pdraw->refcount == 0) {
	    (*pdraw->destroyDrawable)(pdraw);
	    __glxHashDelete(priv->drawHash, gc->currentReadable);
	 }
      }
   }

   gc->currentDrawable = None;
   gc->currentReadable = None;

}

_X_HIDDEN bool
dri2_convert_glx_attribs(unsigned num_attribs, const uint32_t *attribs,
                         unsigned *major_ver, unsigned *minor_ver,
                         uint32_t *render_type, uint32_t *flags, unsigned *api,
                         int *reset, unsigned *error)
{
   unsigned i;
   bool got_profile = false;
   uint32_t profile;

   *major_ver = 1;
   *minor_ver = 0;
   *render_type = GLX_RGBA_TYPE;
   *reset = __DRI_CTX_RESET_NO_NOTIFICATION;
   *flags = 0;
   *api = __DRI_API_OPENGL;

   if (num_attribs == 0) {
      return true;
   }

   /* This is actually an internal error, but what the heck.
    */
   if (attribs == NULL) {
      *error = __DRI_CTX_ERROR_UNKNOWN_ATTRIBUTE;
      return false;
   }

   for (i = 0; i < num_attribs; i++) {
      switch (attribs[i * 2]) {
      case GLX_CONTEXT_MAJOR_VERSION_ARB:
	 *major_ver = attribs[i * 2 + 1];
	 break;
      case GLX_CONTEXT_MINOR_VERSION_ARB:
	 *minor_ver = attribs[i * 2 + 1];
	 break;
      case GLX_CONTEXT_FLAGS_ARB:
	 *flags = attribs[i * 2 + 1];
	 break;
      case GLX_CONTEXT_PROFILE_MASK_ARB:
	 profile = attribs[i * 2 + 1];
	 got_profile = true;
	 break;
      case GLX_RENDER_TYPE:
         *render_type = attribs[i * 2 + 1];
	 break;
      case GLX_CONTEXT_RESET_NOTIFICATION_STRATEGY_ARB:
         switch (attribs[i * 2 + 1]) {
         case GLX_NO_RESET_NOTIFICATION_ARB:
            *reset = __DRI_CTX_RESET_NO_NOTIFICATION;
            break;
         case GLX_LOSE_CONTEXT_ON_RESET_ARB:
            *reset = __DRI_CTX_RESET_LOSE_CONTEXT;
            break;
         default:
            *error = __DRI_CTX_ERROR_UNKNOWN_ATTRIBUTE;
            return false;
         }
         break;
      default:
	 /* If an unknown attribute is received, fail.
	  */
	 *error = __DRI_CTX_ERROR_UNKNOWN_ATTRIBUTE;
	 return false;
      }
   }

   if (!got_profile) {
      if (*major_ver > 3 || (*major_ver == 3 && *minor_ver >= 2))
	 *api = __DRI_API_OPENGL_CORE;
   } else {
      switch (profile) {
      case GLX_CONTEXT_CORE_PROFILE_BIT_ARB:
	 /* There are no profiles before OpenGL 3.2.  The
	  * GLX_ARB_create_context_profile spec says:
	  *
	  *     "If the requested OpenGL version is less than 3.2,
	  *     GLX_CONTEXT_PROFILE_MASK_ARB is ignored and the functionality
	  *     of the context is determined solely by the requested version."
	  */
	 *api = (*major_ver > 3 || (*major_ver == 3 && *minor_ver >= 2))
	    ? __DRI_API_OPENGL_CORE : __DRI_API_OPENGL;
	 break;
      case GLX_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB:
	 *api = __DRI_API_OPENGL;
	 break;
      case GLX_CONTEXT_ES_PROFILE_BIT_EXT:
         if (*major_ver >= 3)
            *api = __DRI_API_GLES3;
         else if (*major_ver == 2 && *minor_ver == 0)
            *api = __DRI_API_GLES2;
         else if (*major_ver == 1 && *minor_ver < 2)
            *api = __DRI_API_GLES;
         else {
            *error = __DRI_CTX_ERROR_BAD_API;
            return false;
         }
         break;
      default:
	 *error = __DRI_CTX_ERROR_BAD_API;
	 return false;
      }
   }

   /* Unknown flag value.
    */
   if (*flags & ~(__DRI_CTX_FLAG_DEBUG | __DRI_CTX_FLAG_FORWARD_COMPATIBLE
                  | __DRI_CTX_FLAG_ROBUST_BUFFER_ACCESS)) {
      *error = __DRI_CTX_ERROR_UNKNOWN_FLAG;
      return false;
   }

   /* There are no forward-compatible contexts before OpenGL 3.0.  The
    * GLX_ARB_create_context spec says:
    *
    *     "Forward-compatible contexts are defined only for OpenGL versions
    *     3.0 and later."
    */
   if (*major_ver < 3 && (*flags & __DRI_CTX_FLAG_FORWARD_COMPATIBLE) != 0) {
      *error = __DRI_CTX_ERROR_BAD_FLAG;
      return false;
   }

   if (*major_ver >= 3 && *render_type == GLX_COLOR_INDEX_TYPE) {
      *error = __DRI_CTX_ERROR_BAD_FLAG;
      return false;
   }

   *error = __DRI_CTX_ERROR_SUCCESS;
   return true;
}

#endif /* GLX_DIRECT_RENDERING */