docs: Major manual edits to environment vars.

This is a huge page.  The edits I've done here take full advantage of
reStructured text and Sphinx's awesome built-in style for explaining
commands and variables.  Enjoy!

1 files changed, 425 insertions, 179 deletions

diff --git a/docs/envvars.rst b/docs/envvars.rst
index a9db746e79..a1427552e7 100644
--- a/docs/envvars.rst
+++ b/docs/envvars.rst
@@ -8,78 +8,122 @@ but they can sometimes be useful for debugging end-user issues.
 LibGL environment variables
 ---------------------------
 
--  LIBGL\_DEBUG - If defined debug information will be printed to
-   stderr. If set to 'verbose' additional information will be printed.
--  LIBGL\_DRIVERS\_PATH - colon-separated list of paths to search for
+``LIBGL_DEBUG``
+   If defined debug information will be printed to
+   stderr. If set to ``verbose`` additional information will be printed.
+
+``LIBGL_DRIVERS_PATH``
+   colon-separated list of paths to search for
    DRI drivers
--  LIBGL\_ALWAYS\_INDIRECT - if set to \`true\`, forces an indirect
+
+``LIBGL_ALWAYS_INDIRECT``
+   if set to ``true``, forces an indirect
    rendering context/connection.
--  LIBGL\_ALWAYS\_SOFTWARE - if set to \`true\`, always use software
+
+``LIBGL_ALWAYS_SOFTWARE``
+   if set to ``true``, always use software
    rendering
--  LIBGL\_NO\_DRAWARRAYS - if set to \`true\`, do not use DrawArrays GLX
+
+``LIBGL_NO_DRAWARRAYS``
+   if set to ``true``, do not use DrawArrays GLX
    protocol (for debugging)
--  LIBGL\_SHOW\_FPS - print framerate to stdout based on the number of
-   glXSwapBuffers calls per second.
--  LIBGL\_DRI3\_DISABLE - disable DRI3 if set to \`true\`.
+
+``LIBGL_SHOW_FPS``
+   print framerate to stdout based on the number of
+   ``glXSwapBuffers`` calls per second.
+
+``LIBGL_DRI3_DISABLE``
+   disable DRI3 if set to ``true``.
 
 Core Mesa environment variables
 -------------------------------
 
--  MESA\_NO\_ASM - if set, disables all assembly language optimizations
--  MESA\_NO\_MMX - if set, disables Intel MMX optimizations
--  MESA\_NO\_3DNOW - if set, disables AMD 3DNow! optimizations
--  MESA\_NO\_SSE - if set, disables Intel SSE optimizations
--  MESA\_NO\_ERROR - if set to 1, error checking is disabled as per
-   KHR\_no\_error. This will result in undefined behaviour for invalid
+``MESA_NO_ASM``
+   if set, disables all assembly language optimizations
+
+``MESA_NO_MMX``
+   if set, disables Intel MMX optimizations
+
+``MESA_NO_3DNOW``
+   if set, disables AMD 3DNow! optimizations
+
+``MESA_NO_SSE``
+   if set, disables Intel SSE optimizations
+
+``MESA_NO_ERROR``
+   if set to 1, error checking is disabled as per
+   ``KHR_no_error``. This will result in undefined behaviour for invalid
    use of the api, but can reduce CPU use for apps that are known to be
    error free.
--  MESA\_DEBUG - if set, error messages are printed to stderr. For
-   example, if the application generates a GL\_INVALID\_ENUM error, a
+
+``MESA_DEBUG``
+   if set, error messages are printed to stderr. For
+   example, if the application generates a ``GL_INVALID_ENUM`` error, a
    corresponding error message indicating where the error occurred, and
    possibly why, will be printed to stderr.
-   For release builds, MESA\_DEBUG defaults to off (no debug output).
-   MESA\_DEBUG accepts the following comma-separated list of named
-   flags, which adds extra behaviour to just set MESA\_DEBUG=1:
+   For release builds, ``MESA_DEBUG`` defaults to off (no debug output).
+   ``MESA_DEBUG`` accepts the following comma-separated list of named
+   flags, which adds extra behaviour to just set ``MESA_DEBUG=1``:
+
+   ``silent``
+      turn off debug messages. Only useful for debug builds.
 
-   -  silent - turn off debug messages. Only useful for debug builds.
-   -  flush - flush after each drawing command
-   -  incomplete\_tex - extra debug messages when a texture is
+   ``flush``
+      flush after each drawing command
+
+   ``incomplete_tex``
+      extra debug messages when a texture is
       incomplete
-   -  incomplete\_fbo - extra debug messages when a fbo is incomplete
-   -  context - create a debug context (see
-      GLX\_CONTEXT\_DEBUG\_BIT\_ARB) and print error and performance
-      messages to stderr (or MESA\_LOG\_FILE).
 
--  MESA\_LOG\_FILE - specifies a file name for logging all errors,
+   ``incomplete_fbo``
+      extra debug messages when a fbo is incomplete
+
+   ``context``
+      create a debug context (see
+      ``GLX_CONTEXT_DEBUG_BIT_ARB``) and print error and performance
+      messages to stderr (or ``MESA_LOG_FILE``).
+
+``MESA_LOG_FILE``
+   specifies a file name for logging all errors,
    warnings, etc., rather than stderr
--  MESA\_TEX\_PROG - if set, implement conventional texture env modes
+
+``MESA_TEX_PROG``
+   if set, implement conventional texture env modes
    with fragment programs (intended for developers only)
--  MESA\_TNL\_PROG - if set, implement conventional vertex
+
+``MESA_TNL_PROG``
+   if set, implement conventional vertex
    transformation operations with vertex programs (intended for
    developers only). Setting this variable automatically sets the
-   MESA\_TEX\_PROG variable as well.
--  MESA\_EXTENSION\_OVERRIDE - can be used to enable/disable extensions.
-   A value such as "GL\_EXT\_foo -GL\_EXT\_bar" will enable the
-   GL\_EXT\_foo extension and disable the GL\_EXT\_bar extension.
--  MESA\_EXTENSION\_MAX\_YEAR - The GL\_EXTENSIONS string returned by
+   ``MESA_TEX_PROG`` variable as well.
+
+``MESA_EXTENSION_OVERRIDE``
+   can be used to enable/disable extensions.
+   A value such as ``GL_EXT_foo -GL_EXT_bar`` will enable the
+   ``GL_EXT_foo`` extension and disable the ``GL_EXT_bar`` extension.
+
+``MESA_EXTENSION_MAX_YEAR``
+   The ``GL_EXTENSIONS`` string returned by
    Mesa is sorted by extension year. If this variable is set to year X,
    only extensions defined on or before year X will be reported. This is
    to work-around a bug in some games where the extension string is
    copied into a fixed-size buffer without truncating. If the extension
    string is too long, the buffer overrun can cause the game to crash.
    This is a work-around for that.
--  MESA\_GL\_VERSION\_OVERRIDE - changes the value returned by
-   glGetString(GL\_VERSION) and possibly the GL API type.
 
-   -  The format should be MAJOR.MINOR[FC\|COMPAT]
-   -  FC is an optional suffix that indicates a forward compatible
+``MESA_GL_VERSION_OVERRIDE``
+   changes the value returned by
+   ``glGetString(GL_VERSION)`` and possibly the GL API type.
+
+   -  The format should be ``MAJOR.MINOR[FC\|COMPAT]``
+   -  ``FC`` is an optional suffix that indicates a forward compatible
       context. This is only valid for versions >= 3.0.
-   -  COMPAT is an optional suffix that indicates a compatibility
-      context or GL\_ARB\_compatibility support. This is only valid for
+   -  ``COMPAT`` is an optional suffix that indicates a compatibility
+      context or ``GL_ARB_compatibility support``. This is only valid for
       versions >= 3.1.
    -  GL versions <= 3.0 are set to a compatibility (non-Core) profile
    -  GL versions = 3.1, depending on the driver, it may or may not have
-      the ARB\_compatibility extension enabled.
+      the ``ARB_compatibility`` extension enabled.
    -  GL versions >= 3.2 are set to a Core profile
    -  Examples: 2.1, 3.0, 3.0FC, 3.1, 3.1FC, 3.1COMPAT, X.Y, X.YFC,
       X.YCOMPAT.
@@ -90,11 +134,11 @@ Core Mesa environment variables
          3.0.
       -  3.0FC - select a Core+Forward Compatible profile with GL
          version 3.0.
-      -  3.1 - select GL version 3.1 with GL\_ARB\_compatibility enabled
+      -  3.1 - select GL version 3.1 with ``GL_ARB_compatibility`` enabled
          per the driver default.
       -  3.1FC - select GL version 3.1 with forward compatibility and
-         GL\_ARB\_compatibility disabled.
-      -  3.1COMPAT - select GL version 3.1 with GL\_ARB\_compatibility
+         ``GL_ARB_compatibility`` disabled.
+      -  3.1COMPAT - select GL version 3.1 with ``GL_ARB_compatibility``
          enabled.
       -  X.Y - override GL version to X.Y without changing the profile.
       -  X.YFC - select a Core+Forward Compatible profile with GL
@@ -104,49 +148,70 @@ Core Mesa environment variables
    -  Mesa may not really implement all the features of the given
       version. (for developers only)
 
--  MESA\_GLES\_VERSION\_OVERRIDE - changes the value returned by
-   glGetString(GL\_VERSION) for OpenGL ES.
+``MESA_GLES_VERSION_OVERRIDE``
+   changes the value returned by
+   ``glGetString(GL_VERSION)`` for OpenGL ES.
 
-   -  The format should be MAJOR.MINOR
+   -  The format should be ``MAJOR.MINOR``
    -  Examples: 2.0, 3.0, 3.1
    -  Mesa may not really implement all the features of the given
       version. (for developers only)
 
--  MESA\_GLSL\_VERSION\_OVERRIDE - changes the value returned by
-   glGetString(GL\_SHADING\_LANGUAGE\_VERSION). Valid values are
-   integers, such as "130". Mesa will not really implement all the
+``MESA_GLSL_VERSION_OVERRIDE``
+   changes the value returned by
+   ``glGetString(GL_SHADING_LANGUAGE_VERSION)``. Valid values are
+   integers, such as ``130``. Mesa will not really implement all the
    features of the given language version if it's higher than what's
    normally reported. (for developers only)
--  MESA\_GLSL\_CACHE\_DISABLE - if set to \`true\`, disables the GLSL
+
+``MESA_GLSL_CACHE_DISABLE``
+   if set to ``true``, disables the GLSL
    shader cache
--  MESA\_GLSL\_CACHE\_MAX\_SIZE - if set, determines the maximum size of
+
+``MESA_GLSL_CACHE_MAX_SIZE``
+   if set, determines the maximum size of
    the on-disk cache of compiled GLSL programs. Should be set to a
-   number optionally followed by 'K', 'M', or 'G' to specify a size in
+   number optionally followed by ``K``, ``M``, or ``G`` to specify a size in
    kilobytes, megabytes, or gigabytes. By default, gigabytes will be
    assumed. And if unset, a maximum size of 1GB will be used. Note: A
    separate cache might be created for each architecture that Mesa is
    installed for on your system. For example under the default settings
    you may end up with a 1GB cache for x86\_64 and another 1GB cache for
    i386.
--  MESA\_GLSL\_CACHE\_DIR - if set, determines the directory to be used
+
+``MESA_GLSL_CACHE_DIR``
+   if set, determines the directory to be used
    for the on-disk cache of compiled GLSL programs. If this variable is
-   not set, then the cache will be stored in $XDG\_CACHE\_HOME/mesa (if
-   that variable is set), or else within .cache/mesa within the user's
+   not set, then the cache will be stored in ``$XDG_CACHE_HOME/mesa`` (if
+   that variable is set), or else within ``.cache/mesa`` within the user's
    home directory.
--  MESA\_GLSL - `shading language compiler
+
+``MESA_GLSL``
+   `shading language compiler
    options <shading.html#envvars>`__
--  MESA\_NO\_MINMAX\_CACHE - when set, the minmax index cache is
+
+``MESA_NO_MINMAX_CACHE``
+   when set, the minmax index cache is
    globally disabled.
--  MESA\_SHADER\_CAPTURE\_PATH - see `Capturing
+
+``MESA_SHADER_CAPTURE_PATH``
+   see `Capturing
    Shaders <shading.html#capture>`__
--  MESA\_SHADER\_DUMP\_PATH and MESA\_SHADER\_READ\_PATH - see
+
+``MESA_SHADER_DUMP_PATH``
+  .. continues below
+
+``MESA_SHADER_READ_PATH``
+   see
    `Experimenting with Shader Replacements <shading.html#replacement>`__
--  MESA\_VK\_VERSION\_OVERRIDE - changes the Vulkan physical device
-   version as returned in VkPhysicalDeviceProperties::apiVersion.
 
-   -  The format should be MAJOR.MINOR[.PATCH]
+``MESA_VK_VERSION_OVERRIDE``
+   changes the Vulkan physical device
+   version as returned in ``VkPhysicalDeviceProperties::apiVersion``.
+
+   -  The format should be ``MAJOR.MINOR[.PATCH]``
    -  This will not let you force a version higher than the driver's
-      instance versionas advertised by vkEnumerateInstanceVersion
+      instance versions advertised by ``vkEnumerateInstanceVersion``
    -  This can be very useful for debugging but some features may not be
       implemented correctly. (For developers only)
 
@@ -156,90 +221,193 @@ Mesa Xlib driver environment variables
 The following are only applicable to the Mesa Xlib software driver. See
 the `Xlib software driver page <xlibdriver.html>`__ for details.
 
--  MESA\_RGB\_VISUAL - specifies the X visual and depth for RGB mode
--  MESA\_CI\_VISUAL - specifies the X visual and depth for CI mode
--  MESA\_BACK\_BUFFER - specifies how to implement the back color
-   buffer, either "pixmap" or "ximage"
--  MESA\_GAMMA - gamma correction coefficients for red, green, blue
+``MESA_RGB_VISUAL``
+   specifies the X visual and depth for RGB mode
+
+``MESA_CI_VISUAL``
+   specifies the X visual and depth for CI mode
+
+``MESA_BACK_BUFFER``
+   specifies how to implement the back color
+   buffer, either ``pixmap`` or ``ximage``
+
+``MESA_GAMMA``
+   gamma correction coefficients for red, green, blue
    channels
--  MESA\_XSYNC - enable synchronous X behavior (for debugging only)
--  MESA\_GLX\_FORCE\_CI - if set, force GLX to treat 8bpp visuals as CI
+
+``MESA_XSYNC``
+   enable synchronous X behavior (for debugging only)
+
+``MESA_GLX_FORCE_CI``
+   if set, force GLX to treat 8bpp visuals as CI
    visuals
--  MESA\_GLX\_FORCE\_ALPHA - if set, forces RGB windows to have an alpha
+
+``MESA_GLX_FORCE_ALPHA``
+   if set, forces RGB windows to have an alpha
    channel.
--  MESA\_GLX\_DEPTH\_BITS - specifies default number of bits for depth
+
+``MESA_GLX_DEPTH_BITS``
+   specifies default number of bits for depth
    buffer.
--  MESA\_GLX\_ALPHA\_BITS - specifies default number of bits for alpha
+
+``MESA_GLX_ALPHA_BITS``
+   specifies default number of bits for alpha
    channel.
 
 i945/i965 driver environment variables (non-Gallium)
 ----------------------------------------------------
 
--  INTEL\_NO\_HW - if set to 1, prevents batches from being submitted to
+``INTEL_NO_HW``
+   if set to 1, prevents batches from being submitted to
    the hardware. This is useful for debugging hangs, etc.
--  INTEL\_DEBUG - a comma-separated list of named flags, which do
+
+``INTEL_DEBUG``
+   a comma-separated list of named flags, which do
    various things:
 
-   -  ann - annotate IR in assembly dumps
-   -  aub - dump batches into an AUB trace for use with simulation tools
-   -  bat - emit batch information
-   -  blit - emit messages about blit operations
-   -  blorp - emit messages about the blorp operations (blits & clears)
-   -  buf - emit messages about buffer objects
-   -  clip - emit messages about the clip unit (for old gens, includes
+   ``ann``
+      annotate IR in assembly dumps
+
+   ``aub``
+      dump batches into an AUB trace for use with simulation tools
+
+   ``bat``
+      emit batch information
+
+   ``blit``
+      emit messages about blit operations
+
+   ``blorp``
+      emit messages about the blorp operations (blits & clears)
+
+   ``buf``
+      emit messages about buffer objects
+
+   ``clip``
+      emit messages about the clip unit (for old gens, includes
       the CLIP program)
-   -  color - use color in output
-   -  cs - dump shader assembly for compute shaders
-   -  do32 - generate compute shader SIMD32 programs even if workgroup
+
+   ``color``
+      use color in output
+
+   ``cs``
+      dump shader assembly for compute shaders
+
+   ``do32``
+      generate compute shader SIMD32 programs even if workgroup
       size doesn't exceed the SIMD16 limit
-   -  dri - emit messages about the DRI interface
-   -  fbo - emit messages about framebuffers
-   -  fs - dump shader assembly for fragment shaders
-   -  gs - dump shader assembly for geometry shaders
-   -  hex - print instruction hex dump with the disassembly
-   -  l3 - emit messages about the new L3 state during transitions
-   -  miptree - emit messages about miptrees
-   -  no8 - don't generate SIMD8 fragment shader
-   -  no16 - suppress generation of 16-wide fragment shaders. useful for
+
+   ``dri``
+      emit messages about the DRI interface
+
+   ``fbo``
+      emit messages about framebuffers
+   ``fs``
+      dump shader assembly for fragment shaders
+
+   ``gs``
+      dump shader assembly for geometry shaders
+
+   ``hex``
+      print instruction hex dump with the disassembly
+
+   ``l3``
+      emit messages about the new L3 state during transitions
+
+   ``miptree``
+      emit messages about miptrees
+
+   ``no8``
+      don't generate SIMD8 fragment shader
+
+   ``no16``
+      suppress generation of 16-wide fragment shaders. useful for
       debugging broken shaders
-   -  nocompact - disable instruction compaction
-   -  nodualobj - suppress generation of dual-object geometry shader
+
+   ``nocompact``
+      disable instruction compaction
+
+   ``nodualobj``
+      suppress generation of dual-object geometry shader
       code
-   -  norbc - disable single sampled render buffer compression
-   -  optimizer - dump shader assembly to files at each optimization
+
+   ``norbc``
+      disable single sampled render buffer compression
+
+   ``optimizer``
+      dump shader assembly to files at each optimization
       pass and iteration that make progress
-   -  perf - emit messages about performance issues
-   -  perfmon - emit messages about AMD\_performance\_monitor
-   -  pix - emit messages about pixel operations
-   -  prim - emit messages about drawing primitives
-   -  reemit - mark all state dirty on each draw call
-   -  sf - emit messages about the strips & fans unit (for old gens,
+
+   ``perf``
+      emit messages about performance issues
+
+   ``perfmon``
+      emit messages about ``AMD_performance_monitor``
+
+   ``pix``
+      emit messages about pixel operations
+
+   ``prim``
+      emit messages about drawing primitives
+
+   ``reemit``
+      mark all state dirty on each draw call
+
+   ``sf``
+      emit messages about the strips & fans unit (for old gens,
       includes the SF program)
-   -  shader\_time - record how much GPU time is spent in each shader
-   -  spill\_fs - force spilling of all registers in the scalar backend
+
+   ``shader_time``
+      record how much GPU time is spent in each shader
+
+   ``spill_fs``
+      force spilling of all registers in the scalar backend
       (useful to debug spilling code)
-   -  spill\_vec4 - force spilling of all registers in the vec4 backend
+
+   ``spill_vec4``
+      force spilling of all registers in the vec4 backend
       (useful to debug spilling code)
-   -  state - emit messages about state flag tracking
-   -  submit - emit batchbuffer usage statistics
-   -  sync - after sending each batch, emit a message and wait for that
+
+   ``state``
+      emit messages about state flag tracking
+
+   ``submit``
+      emit batchbuffer usage statistics
+
+   ``sync``
+      after sending each batch, emit a message and wait for that
       batch to finish rendering
-   -  tcs - dump shader assembly for tessellation control shaders
-   -  tes - dump shader assembly for tessellation evaluation shaders
-   -  tex - emit messages about textures.
-   -  urb - emit messages about URB setup
-   -  vert - emit messages about vertex assembly
-   -  vs - dump shader assembly for vertex shaders
-
--  INTEL\_SCALAR\_VS (or TCS, TES, GS) - force scalar/vec4 mode for a
+
+   ``tcs``
+      dump shader assembly for tessellation control shaders
+
+   ``tes``
+      dump shader assembly for tessellation evaluation shaders
+
+   ``tex``
+      emit messages about textures.
+
+   ``urb``
+      emit messages about URB setup
+
+   ``vert``
+      emit messages about vertex assembly
+
+   ``vs``
+      dump shader assembly for vertex shaders
+``INTEL_SCALAR_VS`` (or ``TCS``, ``TES``, ``GS``)
+   force scalar/vec4 mode for a
    shader stage (Gen8-9 only)
--  INTEL\_PRECISE\_TRIG - if set to 1, true or yes, then the driver
+
+``INTEL_PRECISE_TRIG``
+   if set to 1, true or yes, then the driver
    prefers accuracy over performance in trig functions.
 
 Radeon driver environment variables (radeon, r200, and r300g)
 -------------------------------------------------------------
 
--  RADEON\_NO\_TCL - if set, disable hardware-accelerated
+``RADEON_NO_TCL``
+   if set, disable hardware-accelerated
    Transform/Clip/Lighting.
 
 EGL environment variables
@@ -251,119 +419,197 @@ EGL <egl.html>`__ page for the details.
 Gallium environment variables
 -----------------------------
 
--  GALLIUM\_HUD - draws various information on the screen, like
+``GALLIUM_HUD``
+   draws various information on the screen, like
    framerate, cpu load, driver statistics, performance counters, etc.
-   Set GALLIUM\_HUD=help and run e.g. glxgears for more info.
--  GALLIUM\_HUD\_PERIOD - sets the hud update rate in seconds (float).
+   Set ``GALLIUM_HUD=help`` and run e.g. ``glxgears`` for more info.
+
+``GALLIUM_HUD_PERIOD``
+   sets the hud update rate in seconds (float).
    Use zero to update every frame. The default period is 1/2 second.
--  GALLIUM\_HUD\_VISIBLE - control default visibility, defaults to true.
--  GALLIUM\_HUD\_TOGGLE\_SIGNAL - toggle visibility via user specified
+
+``GALLIUM_HUD_VISIBLE``
+   control default visibility, defaults to true.
+
+``GALLIUM_HUD_TOGGLE_SIGNAL``
+   toggle visibility via user specified
    signal. Especially useful to toggle hud at specific points of
    application and disable for unencumbered viewing the rest of the
-   time. For example, set GALLIUM\_HUD\_VISIBLE to false and
-   GALLIUM\_HUD\_TOGGLE\_SIGNAL to 10 (SIGUSR1). Use kill -10 <pid> to
-   toggle the hud as desired.
--  GALLIUM\_HUD\_DUMP\_DIR - specifies a directory for writing the
+   time. For example, set ``GALLIUM_HUD_VISIBLE`` to ``false`` and
+   ``GALLIUM_HUD_TOGGLE_SIGNAL`` to ``10`` (``SIGUSR1``). Use ``kill -10 <pid>``
+   to toggle the hud as desired.
+
+``GALLIUM_HUD_DUMP_DIR``
+   specifies a directory for writing the
    displayed hud values into files.
--  GALLIUM\_DRIVER - useful in combination with
-   LIBGL\_ALWAYS\_SOFTWARE=true for choosing one of the software
-   renderers "softpipe", "llvmpipe" or "swr".
--  GALLIUM\_LOG\_FILE - specifies a file for logging all errors,
+
+``GALLIUM_DRIVER``
+   useful in combination with
+   ``LIBGL_ALWAYS_SOFTWARE=true`` for choosing one of the software
+   renderers ``softpipe``, ``llvmpipe`` or ``swr``.
+
+``GALLIUM_LOG_FILE``
+   specifies a file for logging all errors,
    warnings, etc. rather than stderr.
--  GALLIUM\_PRINT\_OPTIONS - if non-zero, print all the Gallium
+
+``GALLIUM_PRINT_OPTIONS``
+   if non-zero, print all the Gallium
    environment variables which are used, and their current values.
--  GALLIUM\_DUMP\_CPU - if non-zero, print information about the CPU on
+
+``GALLIUM_DUMP_CPU``
+   if non-zero, print information about the CPU on
    start-up
--  TGSI\_PRINT\_SANITY - if set, do extra sanity checking on TGSI
+
+``TGSI_PRINT_SANITY``
+   if set, do extra sanity checking on TGSI
    shaders and print any errors to stderr.
--  DRAW\_FSE - ???
--  DRAW\_NO\_FSE - ???
--  DRAW\_USE\_LLVM - if set to zero, the draw module will not use LLVM
+
+``DRAW_FSE``
+   ???
+
+``DRAW_NO_FSE``
+   ???
+
+``DRAW_USE_LLVM``
+   if set to zero, the draw module will not use LLVM
    to execute shaders, vertex fetch, etc.
--  ST\_DEBUG - controls debug output from the Mesa/Gallium state
-   tracker. Setting to "tgsi", for example, will print all the TGSI
-   shaders. See src/mesa/state\_tracker/st\_debug.c for other options.
+
+``ST_DEBUG``
+   controls debug output from the Mesa/Gallium state
+   tracker. Setting to ``tgsi``, for example, will print all the TGSI
+   shaders. See ``src/mesa/state_tracker/st_debug.c`` for other options.
 
 Clover state tracker environment variables
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
--  CLOVER\_EXTRA\_BUILD\_OPTIONS - allows specifying additional compiler
+``CLOVER_EXTRA_BUILD_OPTIONS``
+   allows specifying additional compiler
    and linker options. Specified options are appended after the options
-   set by the OpenCL program in clBuildProgram.
--  CLOVER\_EXTRA\_COMPILE\_OPTIONS - allows specifying additional
+   set by the OpenCL program in ``clBuildProgram``.
+
+``CLOVER_EXTRA_COMPILE_OPTIONS``
+   allows specifying additional
    compiler options. Specified options are appended after the options
-   set by the OpenCL program in clCompileProgram.
--  CLOVER\_EXTRA\_LINK\_OPTIONS - allows specifying additional linker
+   set by the OpenCL program in ``clCompileProgram``.
+
+``CLOVER_EXTRA_LINK_OPTIONS``
+   allows specifying additional linker
    options. Specified options are appended after the options set by the
-   OpenCL program in clLinkProgram.
+   OpenCL program in ``clLinkProgram``.
 
 Softpipe driver environment variables
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
--  SOFTPIPE\_DUMP\_FS - if set, the softpipe driver will print fragment
+``SOFTPIPE_DUMP_FS``
+   if set, the softpipe driver will print fragment
    shaders to stderr
--  SOFTPIPE\_DUMP\_GS - if set, the softpipe driver will print geometry
+
+``SOFTPIPE_DUMP_GS``
+   if set, the softpipe driver will print geometry
    shaders to stderr
--  SOFTPIPE\_NO\_RAST - if set, rasterization is no-op'd. For profiling
+
+``SOFTPIPE_NO_RAST``
+   if set, rasterization is no-op'd. For profiling
    purposes.
--  SOFTPIPE\_USE\_LLVM - if set, the softpipe driver will try to use
+
+``SOFTPIPE_USE_LLVM``
+   if set, the softpipe driver will try to use
    LLVM JIT for vertex shading processing.
 
 LLVMpipe driver environment variables
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
--  LP\_NO\_RAST - if set LLVMpipe will no-op rasterization
--  LP\_DEBUG - a comma-separated list of debug options is accepted. See
+``LP_NO_RAST``
+   if set LLVMpipe will no-op rasterization
+
+``LP_DEBUG``
+   a comma-separated list of debug options is accepted. See
    the source code for details.
--  LP\_PERF - a comma-separated list of options to selectively no-op
+
+``LP_PERF``
+   a comma-separated list of options to selectively no-op
    various parts of the driver. See the source code for details.
--  LP\_NUM\_THREADS - an integer indicating how many threads to use for
+
+``LP_NUM_THREADS``
+   an integer indicating how many threads to use for
    rendering. Zero turns off threading completely. The default value is
    the number of CPU cores present.
 
 VMware SVGA driver environment variables
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
--  SVGA\_FORCE\_SWTNL - force use of software vertex transformation
--  SVGA\_NO\_SWTNL - don't allow software vertex transformation
+``SVGA_FORCE_SWTNL``
+   force use of software vertex transformation
+
+``SVGA_NO_SWTNL``
+   don't allow software vertex transformation
    fallbacks (will often result in incorrect rendering).
--  SVGA\_DEBUG - for dumping shaders, constant buffers, etc. See the
+
+``SVGA_DEBUG``
+   for dumping shaders, constant buffers, etc. See the
    code for details.
--  SVGA\_EXTRA\_LOGGING - if set, enables extra logging to the
+
+``SVGA_EXTRA_LOGGING``
+   if set, enables extra logging to the
    vmware.log file, such as the OpenGL program's name and command line
    arguments.
--  See the driver code for other, lesser-used variables.
+
+See the driver code for other, lesser-used variables.
 
 WGL environment variables
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
--  WGL\_SWAP\_INTERVAL - to set a swap interval, equivalent to calling
-   wglSwapIntervalEXT() in an application. If this environment variable
-   is set, application calls to wglSwapIntervalEXT() will have no
+``WGL_SWAP_INTERVAL``
+   to set a swap interval, equivalent to calling
+   ``wglSwapIntervalEXT()`` in an application. If this environment variable
+   is set, application calls to ``wglSwapIntervalEXT()`` will have no
    effect.
 
 VA-API state tracker environment variables
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
--  VAAPI\_MPEG4\_ENABLED - enable MPEG4 for VA-API, disabled by default.
+``VAAPI_MPEG4_ENABLED``
+   enable MPEG4 for VA-API, disabled by default.
 
 VC4 driver environment variables
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
--  VC4\_DEBUG - a comma-separated list of named flags, which do various
+``VC4_DEBUG``
+   a comma-separated list of named flags, which do various
    things:
 
-   -  cl - dump command list during creation
-   -  qpu - dump generated QPU instructions
-   -  qir - dump QPU IR during program compile
-   -  nir - dump NIR during program compile
-   -  tgsi - dump TGSI during program compile
-   -  shaderdb - dump program compile information for shader-db analysis
-   -  perf - print during performance-related events
-   -  norast - skip actual hardware execution of commands
-   -  always\_flush - flush after each draw call
-   -  always\_sync - wait for finish after each flush
-   -  dump - write a GPU command stream trace file (VC4 simulator only)
+   ``cl``
+      dump command list during creation
+
+   ``qpu``
+      dump generated QPU instructions
+
+   ``qir``
+      dump QPU IR during program compile
+
+   ``nir``
+      dump NIR during program compile
+
+   ``tgsi``
+      dump TGSI during program compile
+
+   ``shaderdb``
+      dump program compile information for shader-db analysis
+
+   ``perf``
+      print during performance-related events
+
+   ``norast``
+      skip actual hardware execution of commands
+
+   ``always_flush``
+      flush after each draw call
+
+   ``always_sync``
+      wait for finish after each flush
+
+   ``dump``
+      write a GPU command stream trace file (VC4 simulator only)
 
 Other Gallium drivers have their own environment variables. These may
 change frequently so the source code should be consulted for details.