path: root/src/mesa/drivers/dri/i915/intel_screen.c

/**************************************************************************
 * 
 * Copyright 2003 Tungsten Graphics, 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 TUNGSTEN GRAPHICS 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.
 * 
 **************************************************************************/

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


#include "intel_screen.h"

#include "intel_tex.h"
#include "intel_span.h"
#include "intel_tris.h"
#include "intel_ioctl.h"

#include "i830_dri.h"

PUBLIC const char __driConfigOptions[] =
DRI_CONF_BEGIN
   DRI_CONF_SECTION_PERFORMANCE
      DRI_CONF_FORCE_S3TC_ENABLE(false)
      DRI_CONF_ALLOW_LARGE_TEXTURES(1)
   DRI_CONF_SECTION_END
DRI_CONF_END;
const GLuint __driNConfigOptions = 2;

#ifdef USE_NEW_INTERFACE
static PFNGLXCREATECONTEXTMODES create_context_modes = NULL;
#endif /*USE_NEW_INTERFACE*/

extern const struct dri_extension card_extensions[];

/**
 * Map all the memory regions described by the screen.
 * \return GL_TRUE if success, GL_FALSE if error.
 */
GLboolean
intelMapScreenRegions(__DRIscreenPrivate *sPriv)
{
   intelScreenPrivate *intelScreen = (intelScreenPrivate *)sPriv->private;

   if (intelScreen->front.handle) {
      if (drmMap(sPriv->fd,
                 intelScreen->front.handle,
                 intelScreen->front.size,
                 (drmAddress *)&intelScreen->front.map) != 0) {
         _mesa_problem(NULL, "drmMap(frontbuffer) failed!");
         return GL_FALSE;
      }
   }
   else {
      _mesa_warning(NULL, "no front buffer handle in intelMapScreenRegions!");
   }

   if (drmMap(sPriv->fd,
              intelScreen->back.handle,
              intelScreen->back.size,
              (drmAddress *)&intelScreen->back.map) != 0) {
      intelUnmapScreenRegions(intelScreen);
      return GL_FALSE;
   }

   if (drmMap(sPriv->fd,
              intelScreen->depth.handle,
              intelScreen->depth.size,
              (drmAddress *)&intelScreen->depth.map) != 0) {
      intelUnmapScreenRegions(intelScreen);
      return GL_FALSE;
   }

   if (drmMap(sPriv->fd,
              intelScreen->tex.handle,
              intelScreen->tex.size,
              (drmAddress *)&intelScreen->tex.map) != 0) {
      intelUnmapScreenRegions(intelScreen);
      return GL_FALSE;
   }

   if (0)
      printf("Mappings:  front: %p  back: %p  depth: %p  tex: %p\n",
          intelScreen->front.map,
          intelScreen->back.map,
          intelScreen->depth.map,
          intelScreen->tex.map);
   return GL_TRUE;
}


void
intelUnmapScreenRegions(intelScreenPrivate *intelScreen)
{
#define REALLY_UNMAP 1
   if (intelScreen->front.map) {
#if REALLY_UNMAP
      if (drmUnmap(intelScreen->front.map, intelScreen->front.size) != 0)
         printf("drmUnmap front failed!\n");
#endif
      intelScreen->front.map = NULL;
   }
   if (intelScreen->back.map) {
#if REALLY_UNMAP
      if (drmUnmap(intelScreen->back.map, intelScreen->back.size) != 0)
         printf("drmUnmap back failed!\n");
#endif
      intelScreen->back.map = NULL;
   }
   if (intelScreen->depth.map) {
#if REALLY_UNMAP
      drmUnmap(intelScreen->depth.map, intelScreen->depth.size);
      intelScreen->depth.map = NULL;
#endif
   }
   if (intelScreen->tex.map) {
#if REALLY_UNMAP
      drmUnmap(intelScreen->tex.map, intelScreen->tex.size);
      intelScreen->tex.map = NULL;
#endif
   }
}


static void
intelPrintDRIInfo(intelScreenPrivate *intelScreen,
                  __DRIscreenPrivate *sPriv,
                  I830DRIPtr gDRIPriv)
{
   fprintf(stderr, "*** Front size:   0x%x  offset: 0x%x  pitch: %d\n",
           intelScreen->front.size, intelScreen->front.offset,
           intelScreen->front.pitch);
   fprintf(stderr, "*** Back size:    0x%x  offset: 0x%x  pitch: %d\n",
           intelScreen->back.size, intelScreen->back.offset,
           intelScreen->back.pitch);
   fprintf(stderr, "*** Depth size:   0x%x  offset: 0x%x  pitch: %d\n",
           intelScreen->depth.size, intelScreen->depth.offset,
           intelScreen->depth.pitch);
   fprintf(stderr, "*** Rotated size: 0x%x  offset: 0x%x  pitch: %d\n",
           intelScreen->rotated.size, intelScreen->rotated.offset,
           intelScreen->rotated.pitch);
   fprintf(stderr, "*** Texture size: 0x%x  offset: 0x%x\n",
           intelScreen->tex.size, intelScreen->tex.offset);
   fprintf(stderr, "*** Memory : 0x%x\n", gDRIPriv->mem);
}


static void
intelPrintSAREA(const drmI830Sarea *sarea)
{
   fprintf(stderr, "SAREA: sarea width %d  height %d\n", sarea->width, sarea->height);
   fprintf(stderr, "SAREA: pitch: %d\n", sarea->pitch);
   fprintf(stderr,
           "SAREA: front offset: 0x%08x  size: 0x%x  handle: 0x%x\n",
           sarea->front_offset, sarea->front_size,
           (unsigned) sarea->front_handle);
   fprintf(stderr,
           "SAREA: back  offset: 0x%08x  size: 0x%x  handle: 0x%x\n",
           sarea->back_offset, sarea->back_size,
           (unsigned) sarea->back_handle);
   fprintf(stderr, "SAREA: depth offset: 0x%08x  size: 0x%x  handle: 0x%x\n",
           sarea->depth_offset, sarea->depth_size,
           (unsigned) sarea->depth_handle);
   fprintf(stderr, "SAREA: tex   offset: 0x%08x  size: 0x%x  handle: 0x%x\n",
           sarea->tex_offset, sarea->tex_size,
           (unsigned) sarea->tex_handle);
   fprintf(stderr, "SAREA: rotation: %d\n", sarea->rotation);
   fprintf(stderr,
           "SAREA: rotated offset: 0x%08x  size: 0x%x\n",
           sarea->rotated_offset, sarea->rotated_size);
   fprintf(stderr, "SAREA: rotated pitch: %d\n", sarea->rotated_pitch);
}


/**
 * A number of the screen parameters are obtained/computed from
 * information in the SAREA.  This function updates those parameters.
 */
void
intelUpdateScreenFromSAREA(intelScreenPrivate *intelScreen,
                           drmI830Sarea *sarea)
{
   intelScreen->width = sarea->width;
   intelScreen->height = sarea->height;

   intelScreen->front.offset = sarea->front_offset;
   intelScreen->front.pitch = sarea->pitch * intelScreen->cpp;
   intelScreen->front.handle = sarea->front_handle;
   intelScreen->front.size = sarea->front_size;

   intelScreen->back.offset = sarea->back_offset;
   intelScreen->back.pitch = sarea->pitch * intelScreen->cpp;
   intelScreen->back.handle = sarea->back_handle;
   intelScreen->back.size = sarea->back_size;
			 
   intelScreen->depth.offset = sarea->depth_offset;
   intelScreen->depth.pitch = sarea->pitch * intelScreen->cpp;
   intelScreen->depth.handle = sarea->depth_handle;
   intelScreen->depth.size = sarea->depth_size;

   intelScreen->tex.offset = sarea->tex_offset;
   intelScreen->logTextureGranularity = sarea->log_tex_granularity;
   intelScreen->tex.handle = sarea->tex_handle;
   intelScreen->tex.size = sarea->tex_size;

   intelScreen->rotated.offset = sarea->rotated_offset;
   intelScreen->rotated.pitch = sarea->rotated_pitch * intelScreen->cpp;
   intelScreen->rotated.size = sarea->rotated_size;
   intelScreen->current_rotation = sarea->rotation;
   matrix23Rotate(&intelScreen->rotMatrix,
                  sarea->width, sarea->height, sarea->rotation);
   intelScreen->rotatedWidth = sarea->virtualX;
   intelScreen->rotatedHeight = sarea->virtualY;

   if (0)
      intelPrintSAREA(sarea);
}


static GLboolean intelInitDriver(__DRIscreenPrivate *sPriv)
{
   intelScreenPrivate *intelScreen;
   I830DRIPtr         gDRIPriv = (I830DRIPtr)sPriv->pDevPriv;
   drmI830Sarea *sarea;
   PFNGLXSCRENABLEEXTENSIONPROC glx_enable_extension =
     (PFNGLXSCRENABLEEXTENSIONPROC) (*dri_interface->getProcAddress("glxEnableExtension"));
   void * const psc = sPriv->psc->screenConfigs;

   if (sPriv->devPrivSize != sizeof(I830DRIRec)) {
      fprintf(stderr,"\nERROR!  sizeof(I830DRIRec) does not match passed size from device driver\n");
      return GL_FALSE;
   }

   /* Allocate the private area */
   intelScreen = (intelScreenPrivate *)CALLOC(sizeof(intelScreenPrivate));
   if (!intelScreen) {
      fprintf(stderr,"\nERROR!  Allocating private area failed\n");
      return GL_FALSE;
   }
   /* parse information in __driConfigOptions */
   driParseOptionInfo (&intelScreen->optionCache,
		       __driConfigOptions, __driNConfigOptions);

   intelScreen->driScrnPriv = sPriv;
   sPriv->private = (void *)intelScreen;
   intelScreen->sarea_priv_offset = gDRIPriv->sarea_priv_offset;
   sarea = (drmI830Sarea *)
         (((GLubyte *)sPriv->pSAREA)+intelScreen->sarea_priv_offset);

   intelScreen->deviceID = gDRIPriv->deviceID;
   intelScreen->mem = gDRIPriv->mem;
   intelScreen->cpp = gDRIPriv->cpp;

   switch (gDRIPriv->bitsPerPixel) {
   case 15: intelScreen->fbFormat = DV_PF_555; break;
   case 16: intelScreen->fbFormat = DV_PF_565; break;
   case 32: intelScreen->fbFormat = DV_PF_8888; break;
   }
			 
   intelUpdateScreenFromSAREA(intelScreen, sarea);

   if (0)
      intelPrintDRIInfo(intelScreen, sPriv, gDRIPriv);

   if (!intelMapScreenRegions(sPriv)) {
      fprintf(stderr,"\nERROR!  mapping regions\n");
      _mesa_free(intelScreen);
      sPriv->private = NULL;
      return GL_FALSE;
   }

   intelScreen->drmMinor = sPriv->drmMinor;

   /* Determine if IRQs are active? */
   {
      int ret;
      drmI830GetParam gp;

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

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

   /* Determine if batchbuffers are allowed */
   {
      int ret;
      drmI830GetParam gp;

      gp.param = I830_PARAM_ALLOW_BATCHBUFFER;
      gp.value = &intelScreen->allow_batchbuffer;

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

   if (glx_enable_extension != NULL) {
      (*glx_enable_extension)( psc, "GLX_SGI_make_current_read" );
      (*glx_enable_extension)( psc, "GLX_MESA_allocate_memory" );
   }
   
   sPriv->psc->allocateMemory = (void *) intelAllocateMemoryMESA;
   sPriv->psc->freeMemory     = (void *) intelFreeMemoryMESA;
   sPriv->psc->memoryOffset   = (void *) intelGetMemoryOffsetMESA;

   return GL_TRUE;
}
		
		
static void intelDestroyScreen(__DRIscreenPrivate *sPriv)
{
   intelScreenPrivate *intelScreen = (intelScreenPrivate *)sPriv->private;

   intelUnmapScreenRegions(intelScreen);
   FREE(intelScreen);
   sPriv->private = NULL;
}


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

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

      struct gl_framebuffer *fb = _mesa_create_framebuffer(mesaVis);

      {
         driRenderbuffer *frontRb
            = driNewRenderbuffer(GL_RGBA,
                                 screen->front.map,
                                 screen->cpp,
                                 screen->front.offset, screen->front.pitch,
                                 driDrawPriv);
         intelSetSpanFunctions(frontRb, mesaVis);
         _mesa_add_renderbuffer(fb, BUFFER_FRONT_LEFT, &frontRb->Base);
      }

      if (mesaVis->doubleBufferMode) {
         driRenderbuffer *backRb
            = driNewRenderbuffer(GL_RGBA,
                                 screen->back.map,
                                 screen->cpp,
                                 screen->back.offset, screen->back.pitch,
                                 driDrawPriv);
         intelSetSpanFunctions(backRb, mesaVis);
         _mesa_add_renderbuffer(fb, BUFFER_BACK_LEFT, &backRb->Base);
      }

      if (mesaVis->depthBits == 16) {
         driRenderbuffer *depthRb
            = driNewRenderbuffer(GL_DEPTH_COMPONENT16,
                                 screen->depth.map,
                                 screen->cpp,
                                 screen->depth.offset, screen->depth.pitch,
                                 driDrawPriv);
         intelSetSpanFunctions(depthRb, mesaVis);
         _mesa_add_renderbuffer(fb, BUFFER_DEPTH, &depthRb->Base);
      }
      else if (mesaVis->depthBits == 24) {
         driRenderbuffer *depthRb
            = driNewRenderbuffer(GL_DEPTH_COMPONENT24,
                                 screen->depth.map,
                                 screen->cpp,
                                 screen->depth.offset, screen->depth.pitch,
                                 driDrawPriv);
         intelSetSpanFunctions(depthRb, mesaVis);
         _mesa_add_renderbuffer(fb, BUFFER_DEPTH, &depthRb->Base);
      }

      if (mesaVis->stencilBits > 0 && !swStencil) {
         driRenderbuffer *stencilRb
            = driNewRenderbuffer(GL_STENCIL_INDEX8_EXT,
                                 screen->depth.map,
                                 screen->cpp,
                                 screen->depth.offset, screen->depth.pitch,
                                 driDrawPriv);
         intelSetSpanFunctions(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;

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

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


/* There are probably better ways to do this, such as an
 * init-designated function to register chipids and createcontext
 * functions.
 */
extern GLboolean i830CreateContext( const __GLcontextModes *mesaVis,
				    __DRIcontextPrivate *driContextPriv,
				    void *sharedContextPrivate);

extern GLboolean i915CreateContext( const __GLcontextModes *mesaVis,
				   __DRIcontextPrivate *driContextPriv,
				   void *sharedContextPrivate);




static GLboolean intelCreateContext( const __GLcontextModes *mesaVis,
				   __DRIcontextPrivate *driContextPriv,
				   void *sharedContextPrivate)
{
   __DRIscreenPrivate *sPriv = driContextPriv->driScreenPriv;
   intelScreenPrivate *intelScreen = (intelScreenPrivate *)sPriv->private;

   switch (intelScreen->deviceID) {
   case PCI_CHIP_845_G:
   case PCI_CHIP_I830_M:
   case PCI_CHIP_I855_GM:
   case PCI_CHIP_I865_G:
      return i830CreateContext( mesaVis, driContextPriv, 
				sharedContextPrivate );

   case PCI_CHIP_I915_G:
   case PCI_CHIP_I915_GM:
   case PCI_CHIP_I945_G:
   case PCI_CHIP_I945_GM:
      return i915CreateContext( mesaVis, driContextPriv, 
			       sharedContextPrivate );
 
   default:
      fprintf(stderr, "Unrecognized deviceID %x\n", intelScreen->deviceID);
      return GL_FALSE;
   }
}


static const struct __DriverAPIRec intelAPI = {
   .InitDriver      = intelInitDriver,
   .DestroyScreen   = intelDestroyScreen,
   .CreateContext   = intelCreateContext,
   .DestroyContext  = intelDestroyContext,
   .CreateBuffer    = intelCreateBuffer,
   .DestroyBuffer   = intelDestroyBuffer,
   .SwapBuffers     = intelSwapBuffers,
   .MakeCurrent     = intelMakeCurrent,
   .UnbindContext   = intelUnbindContext,
   .GetSwapInfo     = NULL,
   .GetMSC          = NULL,
   .WaitForMSC      = NULL,
   .WaitForSBC      = NULL,
   .SwapBuffersMSC  = NULL
};


static __GLcontextModes *
intelFillInModes( 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 Intel 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[3];
   u_int8_t stencil_bits_array[3];


   depth_bits_array[0] = 0;
   depth_bits_array[1] = depth_bits;
   depth_bits_array[2] = 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] = 0;
   stencil_bits_array[2] = (stencil_bits == 0) ? 8 : stencil_bits;

   depth_buffer_factor = ((depth_bits != 0) || (stencil_bits != 0)) ? 3 : 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;
   }
   if ( ! driFillInModes( & m, fb_format, fb_type,
			  depth_bits_array, stencil_bits_array, depth_buffer_factor,
			  back_buffer_modes, back_buffer_factor,
			  GLX_DIRECT_COLOR ) ) {
	fprintf( stderr, "[%s:%u] Error creating FBConfig!\n",
		 __func__, __LINE__ );
	return NULL;
   }

   /* 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, 4, 0 };
   static const __DRIversion dri_expected = { 4, 0, 0 };
   static const __DRIversion drm_expected = { 1, 4, 0 };

   dri_interface = interface;

   if ( ! driCheckDriDdxDrmVersions2( "i915",
				      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, &intelAPI);
   if ( psp != NULL ) {
      I830DRIPtr dri_priv = (I830DRIPtr) psp->pDevPriv;
      *driver_modes = intelFillInModes( 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;
}