src/egl/main/egldriver.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2008 VMware, Inc.
   4  * Copyright 2009-2010 Chia-I Wu <olvaffe@gmail.com>
   5  * Copyright 2010-2011 LunarG, Inc.
   6  * All Rights Reserved.
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a
   9  * copy of this software and associated documentation files (the
  10  * "Software"), to deal in the Software without restriction, including
  11  * without limitation the rights to use, copy, modify, merge, publish,
  12  * distribute, sub license, and/or sell copies of the Software, and to
  13  * permit persons to whom the Software is furnished to do so, subject to
  14  * the following conditions:
  15  *
  16  * The above copyright notice and this permission notice (including the
  17  * next paragraph) shall be included in all copies or substantial portions
  18  * 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 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  25  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  26  * DEALINGS IN THE SOFTWARE.
  27  *
  28  **************************************************************************/
  29
  30
  31 /**
  32  * Functions for choosing and opening/loading device drivers.
  33  */
  34
  35
  36 #include <assert.h>
  37 #include <string.h>
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40 #include "c11/threads.h"
  41
  42 #include "egldefines.h"
  43 #include "egldisplay.h"
  44 #include "egldriver.h"
  45 #include "egllog.h"
  46
  47 #include "util/debug.h"
  48
  49 static mtx_t _eglModuleMutex = _MTX_INITIALIZER_NP;
  50 static _EGLDriver *_eglDriver;
  51
  52 static _EGLDriver *
  53 _eglGetDriver(void)
  54 {
  55    mtx_lock(&_eglModuleMutex);
  56
  57    if (!_eglDriver)
  58       _eglDriver = _eglBuiltInDriver();
  59
  60    mtx_unlock(&_eglModuleMutex);
  61
  62    return _eglDriver;
  63 }
  64
  65 static _EGLDriver *
  66 _eglMatchAndInitialize(_EGLDisplay *dpy)
  67 {
  68    if (_eglGetDriver())
  69       if (_eglDriver->API.Initialize(_eglDriver, dpy))
  70          return _eglDriver;
  71
  72    return NULL;
  73 }
  74
  75 /**
  76  * Match a display to a driver.  The matching is done by finding the first
  77  * driver that can initialize the display.
  78  */
  79 _EGLDriver *
  80 _eglMatchDriver(_EGLDisplay *dpy)
  81 {
  82    _EGLDriver *best_drv;
  83
  84    assert(!dpy->Initialized);
  85
  86    /* set options */
  87    dpy->Options.UseFallback =
  88       env_var_as_boolean("LIBGL_ALWAYS_SOFTWARE", false);
  89
  90    best_drv = _eglMatchAndInitialize(dpy);
  91    if (!best_drv) {
  92       dpy->Options.UseFallback = EGL_TRUE;
  93       best_drv = _eglMatchAndInitialize(dpy);
  94    }
  95
  96    if (best_drv) {
  97       _eglLog(_EGL_DEBUG, "the best driver is %s",
  98             best_drv->Name);
  99       dpy->Driver = best_drv;
 100       dpy->Initialized = EGL_TRUE;
 101    }
 102
 103    return best_drv;
 104 }
 105
 106 __eglMustCastToProperFunctionPointerType
 107 _eglGetDriverProc(const char *procname)
 108 {
 109    if (_eglGetDriver())
 110       return _eglDriver->API.GetProcAddress(_eglDriver, procname);
 111
 112    return NULL;
 113 }
 114
 115 /**
 116  * Unload all drivers.
 117  */
 118 void
 119 _eglUnloadDrivers(void)
 120 {
 121    /* this is called at atexit time */
 122    free(_eglDriver);
 123    _eglDriver = NULL;
 124 }