docs/envvars.html

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  11   <h1>The Mesa 3D Graphics Library</h1>
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  16
  17 <h1>Environment Variables</h1>
  18
  19 <p>
  20 Normally, no environment variables need to be set.  Most of the environment
  21 variables used by Mesa/Gallium are for debugging purposes, but they can
  22 sometimes be useful for debugging end-user issues.
  23 </p>
  24
  25
  26 <h2>LibGL environment variables</h2>
  27
  28 <ul>
  29 <li>LIBGL_DEBUG - If defined debug information will be printed to stderr.
  30    If set to 'verbose' additional information will be printed.
  31 <li>LIBGL_DRIVERS_PATH - colon-separated list of paths to search for DRI drivers
  32 <li>LIBGL_ALWAYS_INDIRECT - forces an indirect rendering context/connection.
  33 <li>LIBGL_ALWAYS_SOFTWARE - if set, always use software rendering
  34 <li>LIBGL_NO_DRAWARRAYS - if set do not use DrawArrays GLX protocol (for debugging)
  35 <li>LIBGL_SHOW_FPS - print framerate to stdout based on the number of glXSwapBuffers
  36     calls per second.
  37 <li>LIBGL_DRI3_DISABLE - disable DRI3 if set (the value does not matter)
  38 </ul>
  39
  40
  41
  42 <h2>Core Mesa environment variables</h2>
  43
  44 <ul>
  45 <li>MESA_NO_ASM - if set, disables all assembly language optimizations
  46 <li>MESA_NO_MMX - if set, disables Intel MMX optimizations
  47 <li>MESA_NO_3DNOW - if set, disables AMD 3DNow! optimizations
  48 <li>MESA_NO_SSE - if set, disables Intel SSE optimizations
  49 <li>MESA_DEBUG - if set, error messages are printed to stderr.  For example,
  50    if the application generates a GL_INVALID_ENUM error, a corresponding error
  51    message indicating where the error occurred, and possibly why, will be
  52    printed to stderr.<br>
  53    If the value of MESA_DEBUG is 'FP' floating point arithmetic errors will
  54    generate exceptions.
  55 <li>MESA_LOG_FILE - specifies a file name for logging all errors, warnings,
  56 etc., rather than stderr
  57 <li>MESA_TEX_PROG - if set, implement conventional texture env modes with
  58 fragment programs (intended for developers only)
  59 <li>MESA_TNL_PROG - if set, implement conventional vertex transformation
  60 operations with vertex programs (intended for developers only).
  61 Setting this variable automatically sets the MESA_TEX_PROG variable as well.
  62 <li>MESA_EXTENSION_OVERRIDE - can be used to enable/disable extensions.
  63 A value such as "GL_EXT_foo -GL_EXT_bar" will enable the GL_EXT_foo extension
  64 and disable the GL_EXT_bar extension.
  65 <li>MESA_EXTENSION_MAX_YEAR - The GL_EXTENSIONS string returned by Mesa is sorted
  66 by extension year.
  67 If this variable is set to year X, only extensions defined on or before year
  68 X will be reported.
  69 This is to work-around a bug in some games where the extension string is
  70 copied into a fixed-size buffer without truncating.
  71 If the extension string is too long, the buffer overrun can cause the game
  72 to crash.
  73 This is a work-around for that.
  74 <li>MESA_GL_VERSION_OVERRIDE - changes the value returned by
  75 glGetString(GL_VERSION) and possibly the GL API type.
  76 <ul>
  77 <li> The format should be MAJOR.MINOR[FC]
  78 <li> FC is an optional suffix that indicates a forward compatible context.
  79 This is only valid for versions &gt;= 3.0.
  80 <li> GL versions &lt; 3.0 are set to a compatibility (non-Core) profile
  81 <li> GL versions = 3.0, see below
  82 <li> GL versions &gt; 3.0 are set to a Core profile
  83 <li> Examples: 2.1, 3.0, 3.0FC, 3.1, 3.1FC
  84 <ul>
  85 <li> 2.1 - select a compatibility (non-Core) profile with GL version 2.1
  86 <li> 3.0 - select a compatibility (non-Core) profile with GL version 3.0
  87 <li> 3.0FC - select a Core+Forward Compatible profile with GL version 3.0
  88 <li> 3.1 - select a Core profile with GL version 3.1
  89 <li> 3.1FC - select a Core+Forward Compatible profile with GL version 3.1
  90 </ul>
  91 <li> Mesa may not really implement all the features of the given version.
  92 (for developers only)
  93 </ul>
  94 <li>MESA_GLSL_VERSION_OVERRIDE - changes the value returned by
  95 glGetString(GL_SHADING_LANGUAGE_VERSION). Valid values are integers, such as
  96 "130".  Mesa will not really implement all the features of the given language version
  97 if it's higher than what's normally reported. (for developers only)
  98 <li>MESA_GLSL - <a href="shading.html#envvars">shading language compiler options</a>
  99 </ul>
 100
 101
 102 <h2>Mesa Xlib driver environment variables</h2>
 103
 104 <p>
 105 The following are only applicable to the Mesa Xlib software driver.
 106 See the <a href="xlibdriver.html">Xlib software driver page</a> for details.
 107 </p>
 108 <ul>
 109 <li>MESA_RGB_VISUAL - specifies the X visual and depth for RGB mode
 110 <li>MESA_CI_VISUAL - specifies the X visual and depth for CI mode
 111 <li>MESA_BACK_BUFFER - specifies how to implement the back color buffer,
 112     either "pixmap" or "ximage"
 113 <li>MESA_GAMMA - gamma correction coefficients for red, green, blue channels
 114 <li>MESA_XSYNC - enable synchronous X behavior (for debugging only)
 115 <li>MESA_GLX_FORCE_CI - if set, force GLX to treat 8bpp visuals as CI visuals
 116 <li>MESA_GLX_FORCE_ALPHA - if set, forces RGB windows to have an alpha channel.
 117 <li>MESA_GLX_DEPTH_BITS - specifies default number of bits for depth buffer.
 118 <li>MESA_GLX_ALPHA_BITS - specifies default number of bits for alpha channel.
 119 </ul>
 120
 121
 122 <h2>i945/i965 driver environment variables (non-Gallium)</h2>
 123
 124 <ul>
 125 <li>INTEL_NO_HW - if set to 1, prevents batches from being submitted to the hardware.
 126    This is useful for debugging hangs, etc.</li>
 127 <li>INTEL_DEBUG - a comma-separated list of named flags, which do various things:
 128 <ul>
 129    <li>tex - emit messages about textures.</li>
 130    <li>state - emit messages about state flag tracking</li>
 131    <li>blit - emit messages about blit operations</li>
 132    <li>miptree - emit messages about miptrees</li>
 133    <li>perf - emit messages about performance issues</li>
 134    <li>perfmon - emit messages about AMD_performance_monitor</li>
 135    <li>bat - emit batch information</li>
 136    <li>pix - emit messages about pixel operations</li>
 137    <li>buf - emit messages about buffer objects</li>
 138    <li>reg - emit messages about regions</li>
 139    <li>fbo - emit messages about framebuffers</li>
 140    <li>fs - dump shader assembly for fragment shaders</li>
 141    <li>gs - dump shader assembly for geometry shaders</li>
 142    <li>sync - emit messages about synchronization</li>
 143    <li>prim - emit messages about drawing primitives</li>
 144    <li>vert - emit messages about vertex assembly</li>
 145    <li>dri - emit messages about the DRI interface</li>
 146    <li>sf - emit messages about the strips &amp; fans unit (for old gens, includes the SF program)</li>
 147    <li>stats - enable statistics counters. you probably actually want perfmon or intel_gpu_top instead.</li>
 148    <li>urb - emit messages about URB setup</li>
 149    <li>vs - dump shader assembly for vertex shaders</li>
 150    <li>clip - emit messages about the clip unit (for old gens, includes the CLIP program)</li>
 151    <li>aub - dump batches into an AUB trace for use with simulation tools</li>
 152    <li>shader_time - record how much GPU time is spent in each shader</li>
 153    <li>no16 - suppress generation of 16-wide fragment shaders. useful for debugging broken shaders</li>
 154    <li>blorp - emit messages about the blorp operations (blits &amp; clears)</li>
 155    <li>nodualobj - suppress generation of dual-object geometry shader code</li>
 156 </ul>
 157 </ul>
 158
 159
 160 <h2>Radeon driver environment variables (radeon, r200, and r300g)</h2>
 161
 162 <ul>
 163 <li>RADEON_NO_TCL - if set, disable hardware-accelerated Transform/Clip/Lighting.
 164 </ul>
 165
 166
 167 <h2>EGL environment variables</h2>
 168
 169 <p>
 170 Mesa EGL supports different sets of environment variables.  See the
 171 <a href="egl.html">Mesa EGL</a> page for the details.
 172 </p>
 173
 174
 175 <h2>Gallium environment variables</h2>
 176
 177 <ul>
 178 <li>GALLIUM_HUD - draws various information on the screen, like framerate,
 179     cpu load, driver statistics, performance counters, etc.
 180     Set GALLIUM_HUD=help and run e.g. glxgears for more info.
 181 <li>GALLIUM_LOG_FILE - specifies a file for logging all errors, warnings, etc.
 182     rather than stderr.
 183 <li>GALLIUM_PRINT_OPTIONS - if non-zero, print all the Gallium environment
 184     variables which are used, and their current values.
 185 <li>GALLIUM_DUMP_CPU - if non-zero, print information about the CPU on start-up
 186 <li>TGSI_PRINT_SANITY - if set, do extra sanity checking on TGSI shaders and
 187     print any errors to stderr.
 188 <LI>DRAW_FSE - ???
 189 <LI>DRAW_NO_FSE - ???
 190 <li>DRAW_USE_LLVM - if set to zero, the draw module will not use LLVM to execute
 191     shaders, vertex fetch, etc.
 192 <li>ST_DEBUG - controls debug output from the Mesa/Gallium state tracker.
 193 Setting to "tgsi", for example, will print all the TGSI shaders.
 194 See src/mesa/state_tracker/st_debug.c for other options.
 195 </ul>
 196
 197 <h3>Softpipe driver environment variables</h3>
 198 <ul>
 199 <li>SOFTPIPE_DUMP_FS - if set, the softpipe driver will print fragment shaders
 200     to stderr
 201 <li>SOFTPIPE_DUMP_GS - if set, the softpipe driver will print geometry shaders
 202     to stderr
 203 <li>SOFTPIPE_NO_RAST - if set, rasterization is no-op'd.  For profiling purposes.
 204 <li>SOFTPIPE_USE_LLVM - if set, the softpipe driver will try to use LLVM JIT for
 205     vertex shading processing.
 206 </ul>
 207
 208
 209 <h3>LLVMpipe driver environment variables</h3>
 210 <ul>
 211 <li>LP_NO_RAST - if set LLVMpipe will no-op rasterization
 212 <li>LP_DEBUG - a comma-separated list of debug options is accepted.  See the
 213     source code for details.
 214 <li>LP_PERF - a comma-separated list of options to selectively no-op various
 215     parts of the driver.  See the source code for details.
 216 <li>LP_NUM_THREADS - an integer indicating how many threads to use for rendering.
 217     Zero turns of threading completely.  The default value is the number of CPU
 218     cores present.
 219 </ul>
 220
 221 <h3>VMware SVGA driver environment variables</h3>
 222 <ul>
 223 <li>SVGA_FORCE_SWTNL - force use of software vertex transformation
 224 <li>SVGA_NO_SWTNL - don't allow software vertex transformation fallbacks
 225 (will often result in incorrect rendering).
 226 <li>SVGA_DEBUG - for dumping shaders, constant buffers, etc.  See the code
 227 for details.
 228 <li>See the driver code for other, lesser-used variables.
 229 </ul>
 230
 231
 232 <p>
 233 Other Gallium drivers have their own environment variables.  These may change
 234 frequently so the source code should be consulted for details.
 235 </p>
 236
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