summaryrefslogtreecommitdiff
path: root/src/mesa/drivers/dri/i830/i830_screen.c
blob: b1a5618f41024d4ffaac833041856861ed90eef0 (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
/**************************************************************************
 * 
 * Copyright 1998-1999 Precision Insight, Inc., Cedar Park, Texas.
 * All Rights Reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 * 
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
 * IN NO EVENT SHALL PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 * 
 * **************************************************************************/
/* $XFree86: xc/lib/GL/mesa/src/drv/i830/i830_screen.c,v 1.3 2002/12/10 01:26:53 dawes Exp $ */

/**
 * \file i830_screen.c
 * 
 * Adapted for use on the I830M by Jeff Hartmann.
 *
 * \author Keith Whitwell <keith@tungstengraphics.com>
 * \author Jeff Hartmann <jhartmann@2d3d.com>
 */


#include "glheader.h"
#include "context.h"
#include "matrix.h"
#include "simple_list.h"
#include "framebuffer.h"
#include "renderbuffer.h"

#include "i830_screen.h"
#include "i830_dri.h"

#include "i830_state.h"
#include "i830_tex.h"
#include "i830_span.h"
#include "i830_tris.h"
#include "i830_ioctl.h"

#include "i830_dri.h"

#include "utils.h"
#include "xmlpool.h"
#include "drirenderbuffer.h"

PUBLIC const char __driConfigOptions[] =
DRI_CONF_BEGIN
    DRI_CONF_SECTION_PERFORMANCE
       DRI_CONF_MAX_TEXTURE_UNITS(4,2,4)
       DRI_CONF_FORCE_S3TC_ENABLE(false)
    DRI_CONF_SECTION_END
DRI_CONF_END;
const GLuint __driNConfigOptions = 2;

extern const struct dri_extension card_extensions[];

static int i830_malloc_proxy_buf(drmBufMapPtr buffers)
{
   char *buffer;
   drmBufPtr buf;
   int i;

   buffer = ALIGN_MALLOC(I830_DMA_BUF_SZ, 32);
   if(buffer == NULL) return -1;
   for(i = 0; i < I830_DMA_BUF_NR; i++) {
      buf = &(buffers->list[i]);
      buf->address = (drmAddress)buffer;
   }

   return 0;
}

static drmBufMapPtr i830_create_empty_buffers(void)
{
   drmBufMapPtr retval;

   retval = (drmBufMapPtr)ALIGN_MALLOC(sizeof(drmBufMap), 32);
   if(retval == NULL) return NULL;
   memset(retval, 0, sizeof(drmBufMap));
   retval->list = (drmBufPtr)ALIGN_MALLOC(sizeof(drmBuf) * I830_DMA_BUF_NR, 32);
   if(retval->list == NULL) {
      FREE(retval);
      return NULL;
   }

   memset(retval->list, 0, sizeof(drmBuf) * I830_DMA_BUF_NR);
   return retval;
}

static void i830PrintDRIInfo(i830ScreenPrivate *i830Screen,
			     __DRIscreenPrivate *sPriv,
			     I830DRIPtr gDRIPriv)
{
   GLuint size = (gDRIPriv->ringSize +
		  i830Screen->textureSize +
		  i830Screen->depth.size +
		  i830Screen->back.size +
		  sPriv->fbSize +
		  I830_DMA_BUF_NR * I830_DMA_BUF_SZ +
		  32768 /* Context Memory */ +
		  16*4096 /* Ring buffer */ +
		  64*1024 /* Scratch buffer */ +
		  4096 /* Cursor */);
   GLuint size_low = (gDRIPriv->ringSize +
		      i830Screen->textureSize +
		      sPriv->fbSize +
		      I830_DMA_BUF_NR * I830_DMA_BUF_SZ +
		      32768 /* Context Memory */ +
		      16*4096 /* Ring buffer */ +
		      64*1024 /* Scratch buffer */);

   fprintf(stderr, "\nFront size : 0x%x\n", sPriv->fbSize);
   fprintf(stderr, "Front offset : 0x%x\n", i830Screen->fbOffset);
   fprintf(stderr, "Back size : 0x%x\n", i830Screen->back.size);
   fprintf(stderr, "Back offset : 0x%x\n", i830Screen->backOffset);
   fprintf(stderr, "Depth size : 0x%x\n", i830Screen->depth.size);
   fprintf(stderr, "Depth offset : 0x%x\n", i830Screen->depthOffset);
   fprintf(stderr, "Texture size : 0x%x\n", i830Screen->textureSize);
   fprintf(stderr, "Texture offset : 0x%x\n", i830Screen->textureOffset);
   fprintf(stderr, "Ring offset : 0x%x\n", gDRIPriv->ringOffset);
   fprintf(stderr, "Ring size : 0x%x\n", gDRIPriv->ringSize);
   fprintf(stderr, "Memory : 0x%x\n", gDRIPriv->mem);
   fprintf(stderr, "Used Memory : low(0x%x) high(0x%x)\n", size_low, size);
}

static GLboolean i830InitDriver(__DRIscreenPrivate *sPriv)
{
   i830ScreenPrivate *i830Screen;
   I830DRIPtr         gDRIPriv = (I830DRIPtr)sPriv->pDevPriv;
   PFNGLXSCRENABLEEXTENSIONPROC glx_enable_extension =
     (PFNGLXSCRENABLEEXTENSIONPROC) (*dri_interface->getProcAddress("glxEnableExtension"));
   void * const psc = sPriv->psc->screenConfigs;


   if ( glx_enable_extension == NULL ) {
      return GL_FALSE;
   }

   /* Allocate the private area */
   i830Screen = (i830ScreenPrivate *)CALLOC(sizeof(i830ScreenPrivate));
   if (!i830Screen) {
      fprintf(stderr,"\nERROR!  Allocating private area failed\n");
      return GL_FALSE;
   }

   /* parse information in __driConfigOptions */
   driParseOptionInfo (&i830Screen->optionCache,
		       __driConfigOptions, __driNConfigOptions);


   i830Screen->driScrnPriv = sPriv;
   sPriv->private = (void *)i830Screen;

   i830Screen->deviceID = gDRIPriv->deviceID;
   i830Screen->width = gDRIPriv->width;
   i830Screen->height = gDRIPriv->height;
   i830Screen->mem = gDRIPriv->mem;
   i830Screen->cpp = gDRIPriv->cpp;
   i830Screen->fbStride = gDRIPriv->fbStride;
   i830Screen->fbOffset = gDRIPriv->fbOffset;
			 
   switch (gDRIPriv->bitsPerPixel) {
   case 15: i830Screen->fbFormat = DV_PF_555; break;
   case 16: i830Screen->fbFormat = DV_PF_565; break;
   case 32: i830Screen->fbFormat = DV_PF_8888; break;
   }
			 
   i830Screen->backOffset = gDRIPriv->backOffset;
   i830Screen->depthOffset = gDRIPriv->depthOffset;
   i830Screen->backPitch = gDRIPriv->auxPitch;
   i830Screen->backPitchBits = gDRIPriv->auxPitchBits;
   i830Screen->textureOffset = gDRIPriv->textureOffset;
   i830Screen->textureSize = gDRIPriv->textureSize;
   i830Screen->logTextureGranularity = gDRIPriv->logTextureGranularity;
			 			    			 

   i830Screen->bufs = i830_create_empty_buffers();
   if(i830Screen->bufs == NULL) {
      fprintf(stderr,"\nERROR: Failed to create empty buffers in %s \n",
	      __FUNCTION__);
      FREE(i830Screen);
      return GL_FALSE;
   }

   /* Check if you need to create a fake buffer */
   if(i830_check_copy(sPriv->fd) == 1) {
      i830_malloc_proxy_buf(i830Screen->bufs);
      i830Screen->use_copy_buf = 1;
   } else {
      i830Screen->use_copy_buf = 0;
   }

   i830Screen->back.handle = gDRIPriv->backbuffer;
   i830Screen->back.size = gDRIPriv->backbufferSize;
			 
   if (drmMap(sPriv->fd,
	      i830Screen->back.handle,
	      i830Screen->back.size,
	      (drmAddress *)&i830Screen->back.map) != 0) {
      fprintf(stderr, "\nERROR: line %d, Function %s, File %s\n",
	      __LINE__, __FUNCTION__, __FILE__);
      FREE(i830Screen);
      sPriv->private = NULL;
      return GL_FALSE;
   }

   i830Screen->depth.handle = gDRIPriv->depthbuffer;
   i830Screen->depth.size = gDRIPriv->depthbufferSize;

   if (drmMap(sPriv->fd, 
	      i830Screen->depth.handle,
	      i830Screen->depth.size,
	      (drmAddress *)&i830Screen->depth.map) != 0) {
      fprintf(stderr, "\nERROR: line %d, Function %s, File %s\n", 
	      __LINE__, __FUNCTION__, __FILE__);
      FREE(i830Screen);
      drmUnmap(i830Screen->back.map, i830Screen->back.size);
      sPriv->private = NULL;
      return GL_FALSE;
   }

   i830Screen->tex.handle = gDRIPriv->textures;
   i830Screen->tex.size = gDRIPriv->textureSize;

   if (drmMap(sPriv->fd,
	      i830Screen->tex.handle,
	      i830Screen->tex.size,
	      (drmAddress *)&i830Screen->tex.map) != 0) {
      fprintf(stderr, "\nERROR: line %d, Function %s, File %s\n",
	      __LINE__, __FUNCTION__, __FILE__);
      FREE(i830Screen);
      drmUnmap(i830Screen->back.map, i830Screen->back.size);
      drmUnmap(i830Screen->depth.map, i830Screen->depth.size);
      sPriv->private = NULL;
      return GL_FALSE;
   }
			 
   i830Screen->sarea_priv_offset = gDRIPriv->sarea_priv_offset;
   
   if (0) i830PrintDRIInfo(i830Screen, sPriv, gDRIPriv);

   i830Screen->drmMinor = sPriv->drmMinor;

   if (sPriv->drmMinor >= 3) {
      int ret;
      drmI830GetParam gp;

      gp.param = I830_PARAM_IRQ_ACTIVE;
      gp.value = &i830Screen->irq_active;

      ret = drmCommandWriteRead( sPriv->fd, DRM_I830_GETPARAM,
				 &gp, sizeof(gp));
      if (ret) {
	 fprintf(stderr, "drmI830GetParam: %d\n", ret);
	 return GL_FALSE;
      }
   }

#if 0
   if (sPriv->drmMinor >= 3) {
      int ret;
      drmI830SetParam sp;

      sp.param = I830_SETPARAM_PERF_BOXES;
      sp.value = (getenv("I830_DO_BOXES") != 0);

      ret = drmCommandWrite( sPriv->fd, DRM_I830_SETPARAM,
			     &sp, sizeof(sp));
      if (ret) 
	 fprintf(stderr, "Couldn't set perfboxes: %d\n", ret);
   }
#endif

   (*glx_enable_extension)( psc, "GLX_SGI_make_current_read" );

   return GL_TRUE;
}
		
		
static void i830DestroyScreen(__DRIscreenPrivate *sPriv)
{
   i830ScreenPrivate *i830Screen = (i830ScreenPrivate *)sPriv->private;

   /* Need to unmap all the bufs and maps here:
    */
   drmUnmap(i830Screen->back.map, i830Screen->back.size);
   drmUnmap(i830Screen->depth.map, i830Screen->depth.size);
   drmUnmap(i830Screen->tex.map, i830Screen->tex.size);
   FREE(i830Screen);
   sPriv->private = NULL;
}


static GLboolean i830CreateBuffer(__DRIscreenPrivate *driScrnPriv,
				  __DRIdrawablePrivate *driDrawPriv,
				  const __GLcontextModes *mesaVis,
				  GLboolean isPixmap )
{
   i830ScreenPrivate *screen = (i830ScreenPrivate *) driScrnPriv->private;

   if (isPixmap) {
      return GL_FALSE; /* not implemented */
   }
   else {
#if 0
      GLboolean swStencil = (mesaVis->stencilBits > 0 && 
			     mesaVis->depthBits != 24);
#else
      GLboolean swStencil = mesaVis->stencilBits > 0;
#endif

#if 0
      driDrawPriv->driverPrivate = (void *) 
	 _mesa_create_framebuffer(mesaVis,
				  GL_FALSE,  /* software depth buffer? */
				  swStencil,
				  mesaVis->accumRedBits > 0,
				  GL_FALSE /* s/w alpha planes */);
#else
      struct gl_framebuffer *fb = _mesa_create_framebuffer(mesaVis);

      {
         driRenderbuffer *frontRb
            = driNewRenderbuffer(GL_RGBA, screen->cpp,
                                 /*screen->frontOffset*/0, screen->backPitch);
         i830SetSpanFunctions(frontRb, mesaVis);
         _mesa_add_renderbuffer(fb, BUFFER_FRONT_LEFT, &frontRb->Base);
      }

      if (mesaVis->doubleBufferMode) {
         driRenderbuffer *backRb
            = driNewRenderbuffer(GL_RGBA, screen->cpp,
                                 screen->backOffset, screen->backPitch);
         i830SetSpanFunctions(backRb, mesaVis);
         _mesa_add_renderbuffer(fb, BUFFER_BACK_LEFT, &backRb->Base);
      }

      if (mesaVis->depthBits == 16) {
         driRenderbuffer *depthRb
            = driNewRenderbuffer(GL_DEPTH_COMPONENT16, screen->cpp,
                                 screen->depthOffset, screen->backPitch);
         i830SetSpanFunctions(depthRb, mesaVis);
         _mesa_add_renderbuffer(fb, BUFFER_DEPTH, &depthRb->Base);
      }
      else if (mesaVis->depthBits == 24) {
         if (mesaVis->stencilBits == 8) {
            driRenderbuffer *depthRb
               = driNewRenderbuffer(GL_DEPTH_COMPONENT24, screen->cpp,
                                    screen->depthOffset, screen->backPitch);
            i830SetSpanFunctions(depthRb, mesaVis);
            _mesa_add_renderbuffer(fb, BUFFER_DEPTH, &depthRb->Base);
         }
         else {
            /* not really 32-bit Z, but use GL_DEPTH_COMPONENT32 anyway */
            driRenderbuffer *depthRb
               = driNewRenderbuffer(GL_DEPTH_COMPONENT32, screen->cpp,
                                    screen->depthOffset, screen->backPitch);
            i830SetSpanFunctions(depthRb, mesaVis);
            _mesa_add_renderbuffer(fb, BUFFER_DEPTH, &depthRb->Base);
         }
      }

      if (mesaVis->stencilBits > 0 && !swStencil) {
         driRenderbuffer *stencilRb
            = driNewRenderbuffer(GL_STENCIL_INDEX8_EXT, screen->cpp,
                                    screen->depthOffset, screen->backPitch);
         i830SetSpanFunctions(stencilRb, mesaVis);
         _mesa_add_renderbuffer(fb, BUFFER_STENCIL, &stencilRb->Base);
      }

      _mesa_add_soft_renderbuffers(fb,
                                   GL_FALSE, /* color */
                                   GL_FALSE, /* depth */
                                   swStencil,
                                   mesaVis->accumRedBits > 0,
                                   GL_FALSE, /* alpha */
                                   GL_FALSE /* aux */);
      driDrawPriv->driverPrivate = (void *) fb;
#endif

      return (driDrawPriv->driverPrivate != NULL);
   }
}

static void i830DestroyBuffer(__DRIdrawablePrivate *driDrawPriv)
{
   _mesa_destroy_framebuffer((GLframebuffer *) (driDrawPriv->driverPrivate));
}

static const struct __DriverAPIRec i830API = {
   .InitDriver      = i830InitDriver,
   .DestroyScreen   = i830DestroyScreen,
   .CreateContext   = i830CreateContext,
   .DestroyContext  = i830DestroyContext,
   .CreateBuffer    = i830CreateBuffer,
   .DestroyBuffer   = i830DestroyBuffer,
   .SwapBuffers     = i830SwapBuffers,
   .MakeCurrent     = i830MakeCurrent,
   .UnbindContext   = i830UnbindContext,
   .GetSwapInfo     = NULL,
   .GetMSC          = NULL,
   .WaitForMSC      = NULL,
   .WaitForSBC      = NULL,
   .SwapBuffersMSC  = NULL
};


static __GLcontextModes *
i830FillInModes( unsigned pixel_bits, unsigned depth_bits,
		 unsigned stencil_bits, GLboolean have_back_buffer )
{
   __GLcontextModes * modes;
   __GLcontextModes * m;
   unsigned num_modes;
   unsigned depth_buffer_factor;
   unsigned back_buffer_factor;
   GLenum fb_format;
   GLenum fb_type;

   /* GLX_SWAP_COPY_OML is only supported because the MGA driver doesn't
    * support pageflipping at all.
    */
   static const GLenum back_buffer_modes[] = {
      GLX_NONE, GLX_SWAP_UNDEFINED_OML, GLX_SWAP_COPY_OML
   };

   u_int8_t depth_bits_array[2];
   u_int8_t stencil_bits_array[2];


   depth_bits_array[0] = 0;
   depth_bits_array[1] = depth_bits;

   /* Just like with the accumulation buffer, always provide some modes
    * with a stencil buffer.  It will be a sw fallback, but some apps won't
    * care about that.
    */
   stencil_bits_array[0] = 0;
   stencil_bits_array[1] = (stencil_bits == 0) ? 8 : stencil_bits;

   depth_buffer_factor = ((depth_bits != 0) || (stencil_bits != 0)) ? 2 : 1;
   back_buffer_factor  = (have_back_buffer) ? 3 : 1;

   num_modes = depth_buffer_factor * back_buffer_factor * 4;

    if ( pixel_bits == 16 ) {
        fb_format = GL_RGB;
        fb_type = GL_UNSIGNED_SHORT_5_6_5;
    }
    else {
        fb_format = GL_BGRA;
        fb_type = GL_UNSIGNED_INT_8_8_8_8_REV;
    }

   modes = (*dri_interface->createContextModes)( num_modes, sizeof( __GLcontextModes ) );
   m = modes;
   if ( ! driFillInModes( & m, fb_format, fb_type,
			  depth_bits_array, stencil_bits_array, depth_buffer_factor,
			  back_buffer_modes, back_buffer_factor,
			  GLX_TRUE_COLOR ) ) {
	fprintf( stderr, "[%s:%u] Error creating FBConfig!\n",
		 __func__, __LINE__ );
	return NULL;
    }

   /* There's no direct color modes on i830? */

   /* Mark the visual as slow if there are "fake" stencil bits.
    */
   for ( m = modes ; m != NULL ; m = m->next ) {
      if ( (m->stencilBits != 0) && (m->stencilBits != stencil_bits) ) {
	 m->visualRating = GLX_SLOW_CONFIG;
      }
   }

   return modes;
}


/**
 * This is the bootstrap function for the driver.  libGL supplies all of the
 * requisite information about the system, and the driver initializes itself.
 * This routine also fills in the linked list pointed to by \c driver_modes
 * with the \c __GLcontextModes that the driver can support for windows or
 * pbuffers.
 * 
 * \return A pointer to a \c __DRIscreenPrivate on success, or \c NULL on 
 *         failure.
 */
PUBLIC
void * __driCreateNewScreen_20050727( __DRInativeDisplay *dpy, int scrn, __DRIscreen *psc,
			     const __GLcontextModes * modes,
			     const __DRIversion * ddx_version,
			     const __DRIversion * dri_version,
			     const __DRIversion * drm_version,
			     const __DRIframebuffer * frame_buffer,
			     drmAddress pSAREA, int fd, 
			     int internal_api_version,
			     const __DRIinterfaceMethods * interface,
			     __GLcontextModes ** driver_modes )
			     
{
   __DRIscreenPrivate *psp;
   static const __DRIversion ddx_expected = { 1, 0, 0 };
   static const __DRIversion dri_expected = { 4, 0, 0 };
   static const __DRIversion drm_expected = { 1, 3, 0 };

   dri_interface = interface;

   if ( ! driCheckDriDdxDrmVersions2( "i830",
				      dri_version, & dri_expected,
				      ddx_version, & ddx_expected,
				      drm_version, & drm_expected ) ) {
      return NULL;
   }

   psp = __driUtilCreateNewScreen(dpy, scrn, psc, NULL,
				  ddx_version, dri_version, drm_version,
				  frame_buffer, pSAREA, fd,
				  internal_api_version, &i830API);
   if ( psp != NULL ) {
      I830DRIPtr dri_priv = (I830DRIPtr) psp->pDevPriv;
      *driver_modes = i830FillInModes( dri_priv->cpp * 8,
				       (dri_priv->cpp == 2) ? 16 : 24,
				       (dri_priv->cpp == 2) ? 0  : 8,
				       (dri_priv->backOffset != dri_priv->depthOffset) );

      /* Calling driInitExtensions here, with a NULL context pointer, does not actually
       * enable the extensions.  It just makes sure that all the dispatch offsets for all
       * the extensions that *might* be enables are known.  This is needed because the
       * dispatch offsets need to be known when _mesa_context_create is called, but we can't
       * enable the extensions until we have a context pointer.
       *
       * Hello chicken.  Hello egg.  How are you two today?
       */
      driInitExtensions( NULL, card_extensions, GL_FALSE );
   }

   return (void *) psp;
}