docs/envvars.html

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   9 <H1>Environment Variables</H1>
  10
  11 <p>
  12 Normally, no environment variables need to be set.  Most of the environment
  13 variables used by Mesa/Gallium are for debugging purposes, but they can
  14 sometimes be useful for debugging end-user issues.
  15 </p>
  16
  17
  18 <H2>LibGL environment variables</H2>
  19
  20 <ul>
  21 <li>LIBGL_DEBUG - If defined debug information will be printed to stderr.
  22    If set to 'verbose' additional information will be printed.
  23 <li>LIBGL_DRIVERS_PATH - colon-separated list of paths to search for DRI drivers
  24 <li>LIBGL_ALWAYS_INDIRECT - forces an indirect rendering context/connection.
  25 <li>LIBGL_ALWAYS_SOFTWARE - if set, always use software rendering
  26 <li>LIBGL_NO_DRAWARRAYS - if set do not use DrawArrays GLX protocol (for debugging)
  27 </ul>
  28
  29
  30
  31 <H2>Core Mesa environment variables</H2>
  32
  33 <ul>
  34 <li>MESA_NO_ASM - if set, disables all assembly language optimizations
  35 <li>MESA_NO_MMX - if set, disables Intel MMX optimizations
  36 <li>MESA_NO_3DNOW - if set, disables AMD 3DNow! optimizations
  37 <li>MESA_NO_SSE - if set, disables Intel SSE optimizations
  38 <li>MESA_DEBUG - if set, error messages are printed to stderr.  For example,
  39    if the application generates a GL_INVALID_ENUM error, a corresponding error
  40    message indicating where the error occured, and possibly why, will be
  41    printed to stderr.<br>
  42    If the value of MESA_DEBUG is 'FP' floating point arithmetic errors will
  43    generate exceptions.
  44 <li>MESA_TEX_PROG - if set, implement conventional texture env modes with
  45 fragment programs (intended for developers only)
  46 <li>MESA_TNL_PROG - if set, implement conventional vertex transformation
  47 operations with vertex programs (intended for developers only).
  48 Setting this variable automatically sets the MESA_TEX_PROG variable as well.
  49 <li>MESA_EXTENSION_OVERRIDE - can be used to enable/disable extensions.
  50 A value such as "GL_EXT_foo -GL_EXT_bar" will enable the GL_EXT_foo extension
  51 and disable the GL_EXT_bar extension.
  52 <li>MESA_EXTENSION_MAX_YEAR - The GL_EXTENSIONS string returned by Mesa is sorted
  53 by extension year.
  54 If this variable is set to year X, only extensions defined on or before year
  55 X will be reported.
  56 This is to work-around a bug in some games where the extension string is
  57 copied into a fixed-size buffer without truncating.
  58 If the extension string is too long, the buffer overrun can cause the game
  59 to crash.
  60 This is a work-around for that.
  61 <li>MESA_GL_VERSION_OVERRIDE - changes the value returned by
  62 glGetString(GL_VERSION). Valid values are point-separated version numbers,
  63 such as "3.0". Mesa will not really implement all the features of the given
  64 version if it's higher than what's normally reported.
  65 <li>MESA_GLSL_VERSION_OVERRIDE - changes the value returned by
  66 glGetString(GL_SHADING_LANGUAGE_VERSION). Valid values are integers, such as
  67 "130".  Mesa will not really implement all the features of the given language version
  68 if it's higher than what's normally reported. (for developers only)
  69 <li>MESA_GLSL - <a href="shading.html#envvars">shading language compiler options</a>
  70 </ul>
  71
  72
  73 <H2>Mesa Xlib driver environment variables</H2>
  74
  75 <p>
  76 The following are only applicable to the Mesa Xlib software driver.
  77 See the <A HREF="xlibdriver.html">Xlib software driver page</A> for details.
  78 </p>
  79 <ul>
  80 <li>MESA_RGB_VISUAL - specifies the X visual and depth for RGB mode
  81 <li>MESA_CI_VISUAL - specifies the X visual and depth for CI mode
  82 <li>MESA_BACK_BUFFER - specifies how to implement the back color buffer,
  83     either "pixmap" or "ximage"
  84 <li>MESA_GAMMA - gamma correction coefficients for red, green, blue channels
  85 <li>MESA_XSYNC - enable synchronous X behavior (for debugging only)
  86 <li>MESA_GLX_FORCE_CI - if set, force GLX to treat 8bpp visuals as CI visuals
  87 <li>MESA_GLX_FX - set to either "fullscreen" for full-screen rendering,
  88   "window" to render into a window, or "disable" to disable the Glide driver.
  89 <li>MESA_GLX_FORCE_ALPHA - if set, forces RGB windows to have an alpha channel.
  90 <li>MESA_GLX_DEPTH_BITS - specifies default number of bits for depth buffer.
  91 <li>MESA_GLX_ALPHA_BITS - specifies default number of bits for alpha channel.
  92 </ul>
  93
  94
  95 <h2>i945/i965 driver environment variables (non-Gallium)</h2>
  96
  97 <ul>
  98 <li>INTEL_STRICT_CONFORMANCE - if set to 1, enable sw fallbacks to improve
  99     OpenGL conformance.  If set to 2, always use software rendering.
 100 <li>INTEL_NO_BLIT - if set, disable hardware-accelerated glBitmap,
 101     glCopyPixels, glDrawPixels.
 102 </ul>
 103
 104
 105 <h2>Radeon R300 driver environment variables (non-Gallium)</h2>
 106
 107 <ul>
 108 <li>R300_NO_TCL - if set, disable hardware-accelerated Transform/Clip/Lighting.
 109 </ul>
 110
 111
 112 <h2>EGL environment variables</h2>
 113
 114 <p>
 115 Mesa EGL supports different sets of environment variables.  See the
 116 <a href="egl.html">Mesa EGL</a> page for the details.
 117 </p>
 118
 119
 120 <h2>Gallium environment variables</h2>
 121
 122 <ul>
 123 <li>GALLIUM_PRINT_OPTIONS - if non-zero, print all the Gallium environment
 124     variables which are used, and their current values.
 125 <li>GALLIUM_NOSSE - if non-zero, do not use SSE runtime code generation for
 126     shader execution
 127 <li>GALLIUM_NOPPC - if non-zero, do not use PPC runtime code generation for
 128     shader execution
 129 <li>GALLIUM_DUMP_CPU - if non-zero, print information about the CPU on start-up
 130 <li>TGSI_PRINT_SANITY - if set, do extra sanity checking on TGSI shaders and
 131     print any errors to stderr.
 132 <LI>DRAW_FSE - ???
 133 <LI>DRAW_NO_FSE - ???
 134 <li>DRAW_USE_LLVM - if set to zero, the draw module will not use LLVM to execute
 135     shaders, vertex fetch, etc.
 136 </ul>
 137
 138 <h3>Softpipe driver environment variables</h3>
 139 <ul>
 140 <li>SOFTPIPE_DUMP_FS - if set, the softpipe driver will print fragment shaders
 141     to stderr
 142 <li>SOFTPIPE_DUMP_GS - if set, the softpipe driver will print geometry shaders
 143     to stderr
 144 <li>SOFTPIPE_NO_RAST - if set, rasterization is no-op'd.  For profiling purposes.
 145 </ul>
 146
 147
 148 <h3>LLVMpipe driver environment variables</h3>
 149 <ul>
 150 <li>LP_NO_RAST - if set LLVMpipe will no-op rasterization
 151 <li>LP_DEBUG - a comma-separated list of debug options is acceptec.  See the
 152     source code for details.
 153 <li>LP_PERF - a comma-separated list of options to selectively no-op various
 154     parts of the driver.  See the source code for details.
 155 <li>LP_NUM_THREADS - an integer indicating how many threads to use for rendering.
 156     Zero turns of threading completely.  The default value is the number of CPU
 157     cores present.
 158 </ul>
 159
 160
 161 <p>
 162 Other Gallium drivers have their own environment variables.  These may change
 163 frequently so the source code should be consulted for details.
 164 </p>
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