docs/envvars.html - platform/external/mesa3d - Git at Google

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 <h1>Environment Variables</h1>

 <p>
 Normally, no environment variables need to be set.  Most of the environment
 variables used by Mesa/Gallium are for debugging purposes, but they can
 sometimes be useful for debugging end-user issues.
 </p>


 <h2>LibGL environment variables</h2>

 <ul>
 <li>LIBGL_DEBUG - If defined debug information will be printed to stderr.
    If set to 'verbose' additional information will be printed.
 <li>LIBGL_DRIVERS_PATH - colon-separated list of paths to search for DRI drivers
 <li>LIBGL_ALWAYS_INDIRECT - forces an indirect rendering context/connection.
 <li>LIBGL_ALWAYS_SOFTWARE - if set, always use software rendering
 <li>LIBGL_NO_DRAWARRAYS - if set do not use DrawArrays GLX protocol (for debugging)
 </ul>


 <h2>Core Mesa environment variables</h2>

 <ul>
 <li>MESA_NO_ASM - if set, disables all assembly language optimizations
 <li>MESA_NO_MMX - if set, disables Intel MMX optimizations
 <li>MESA_NO_3DNOW - if set, disables AMD 3DNow! optimizations
 <li>MESA_NO_SSE - if set, disables Intel SSE optimizations
 <li>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 occured, and possibly why, will be
    printed to stderr.<br>
    If the value of MESA_DEBUG is 'FP' floating point arithmetic errors will
    generate exceptions.
 <li>MESA_LOG_FILE - specifies a file name for logging all errors, warnings,
 etc., rather than stderr
 <li>MESA_TEX_PROG - if set, implement conventional texture env modes with
 fragment programs (intended for developers only)
 <li>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.
 <li>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.
 <li>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.
 <li>MESA_GL_VERSION_OVERRIDE - changes the value returned by
 glGetString(GL_VERSION). Valid values are point-separated version numbers,
 such as "3.0". Mesa will not really implement all the features of the given
 version if it's higher than what's normally reported.
 <li>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)
 <li>MESA_GLSL - <a href="shading.html#envvars">shading language compiler options</a>
 </ul>


 <h2>Mesa Xlib driver environment variables</h2>

 <p>
 The following are only applicable to the Mesa Xlib software driver.
 See the <a href="xlibdriver.html">Xlib software driver page</a> for details.
 </p>
 <ul>
 <li>MESA_RGB_VISUAL - specifies the X visual and depth for RGB mode
 <li>MESA_CI_VISUAL - specifies the X visual and depth for CI mode
 <li>MESA_BACK_BUFFER - specifies how to implement the back color buffer,
     either "pixmap" or "ximage"
 <li>MESA_GAMMA - gamma correction coefficients for red, green, blue channels
 <li>MESA_XSYNC - enable synchronous X behavior (for debugging only)
 <li>MESA_GLX_FORCE_CI - if set, force GLX to treat 8bpp visuals as CI visuals
 <li>MESA_GLX_FORCE_ALPHA - if set, forces RGB windows to have an alpha channel.
 <li>MESA_GLX_DEPTH_BITS - specifies default number of bits for depth buffer.
 <li>MESA_GLX_ALPHA_BITS - specifies default number of bits for alpha channel.
 </ul>


 <h2>i945/i965 driver environment variables (non-Gallium)</h2>

 <ul>
 <li>INTEL_STRICT_CONFORMANCE - if set to 1, enable sw fallbacks to improve
     OpenGL conformance.  If set to 2, always use software rendering.
 <li>INTEL_NO_BLIT - if set, disable hardware-accelerated glBitmap,
     glCopyPixels, glDrawPixels.
 </ul>


 <h2>Radeon driver environment variables (radeon, r200, and r300g)</h2>

 <ul>
 <li>RADEON_NO_TCL - if set, disable hardware-accelerated Transform/Clip/Lighting.
 </ul>


 <h2>EGL environment variables</h2>

 <p>
 Mesa EGL supports different sets of environment variables.  See the
 <a href="egl.html">Mesa EGL</a> page for the details.
 </p>


 <h2>Gallium environment variables</h2>

 <ul>
 <li>GALLIUM_LOG_FILE - specifies a file for logging all errors, warnings, etc.
     rather than stderr.
 <li>GALLIUM_PRINT_OPTIONS - if non-zero, print all the Gallium environment
     variables which are used, and their current values.
 <li>GALLIUM_NOSSE - if non-zero, do not use SSE runtime code generation for
     shader execution
 <li>GALLIUM_NOPPC - if non-zero, do not use PPC runtime code generation for
     shader execution
 <li>GALLIUM_DUMP_CPU - if non-zero, print information about the CPU on start-up
 <li>TGSI_PRINT_SANITY - if set, do extra sanity checking on TGSI shaders and
     print any errors to stderr.
 <LI>DRAW_FSE - ???
 <LI>DRAW_NO_FSE - ???
 <li>DRAW_USE_LLVM - if set to zero, the draw module will not use LLVM to execute
     shaders, vertex fetch, etc.
 </ul>

 <h3>Softpipe driver environment variables</h3>
 <ul>
 <li>SOFTPIPE_DUMP_FS - if set, the softpipe driver will print fragment shaders
     to stderr
 <li>SOFTPIPE_DUMP_GS - if set, the softpipe driver will print geometry shaders
     to stderr
 <li>SOFTPIPE_NO_RAST - if set, rasterization is no-op'd.  For profiling purposes.
 <li>SOFTPIPE_USE_LLVM - if set, the softpipe driver will try to use LLVM JIT for
     vertex shading procesing.
 </ul>


 <h3>LLVMpipe driver environment variables</h3>
 <ul>
 <li>LP_NO_RAST - if set LLVMpipe will no-op rasterization
 <li>LP_DEBUG - a comma-separated list of debug options is acceptec.  See the
     source code for details.
 <li>LP_PERF - a comma-separated list of options to selectively no-op various
     parts of the driver.  See the source code for details.
 <li>LP_NUM_THREADS - an integer indicating how many threads to use for rendering.
     Zero turns of threading completely.  The default value is the number of CPU
     cores present.
 </ul>


 <p>
 Other Gallium drivers have their own environment variables.  These may change
 frequently so the source code should be consulted for details.
 </p>

 </body>
 </html>
	<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
	<html lang="en">
	<head>
	<meta http-equiv="content-type" content="text/html; charset=utf-8">
	<title>Environment Variables</title>
	<link rel="stylesheet" type="text/css" href="mesa.css">
	</head>
	<body>

	<h1>Environment Variables</h1>

	<p>
	Normally, no environment variables need to be set. Most of the environment
	variables used by Mesa/Gallium are for debugging purposes, but they can
	sometimes be useful for debugging end-user issues.
	</p>


	<h2>LibGL environment variables</h2>

	<ul>
	<li>LIBGL_DEBUG - If defined debug information will be printed to stderr.
	If set to 'verbose' additional information will be printed.
	<li>LIBGL_DRIVERS_PATH - colon-separated list of paths to search for DRI drivers
	<li>LIBGL_ALWAYS_INDIRECT - forces an indirect rendering context/connection.
	<li>LIBGL_ALWAYS_SOFTWARE - if set, always use software rendering
	<li>LIBGL_NO_DRAWARRAYS - if set do not use DrawArrays GLX protocol (for debugging)
	</ul>



	<h2>Core Mesa environment variables</h2>

	<ul>
	<li>MESA_NO_ASM - if set, disables all assembly language optimizations
	<li>MESA_NO_MMX - if set, disables Intel MMX optimizations
	<li>MESA_NO_3DNOW - if set, disables AMD 3DNow! optimizations
	<li>MESA_NO_SSE - if set, disables Intel SSE optimizations
	<li>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 occured, and possibly why, will be
	printed to stderr.<br>
	If the value of MESA_DEBUG is 'FP' floating point arithmetic errors will
	generate exceptions.
	<li>MESA_LOG_FILE - specifies a file name for logging all errors, warnings,
	etc., rather than stderr
	<li>MESA_TEX_PROG - if set, implement conventional texture env modes with
	fragment programs (intended for developers only)
	<li>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.
	<li>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.
	<li>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.
	<li>MESA_GL_VERSION_OVERRIDE - changes the value returned by
	glGetString(GL_VERSION). Valid values are point-separated version numbers,
	such as "3.0". Mesa will not really implement all the features of the given
	version if it's higher than what's normally reported.
	<li>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)
	<li>MESA_GLSL - <a href="shading.html#envvars">shading language compiler options</a>
	</ul>


	<h2>Mesa Xlib driver environment variables</h2>

	<p>
	The following are only applicable to the Mesa Xlib software driver.
	See the <a href="xlibdriver.html">Xlib software driver page</a> for details.
	</p>
	<ul>
	<li>MESA_RGB_VISUAL - specifies the X visual and depth for RGB mode
	<li>MESA_CI_VISUAL - specifies the X visual and depth for CI mode
	<li>MESA_BACK_BUFFER - specifies how to implement the back color buffer,
	either "pixmap" or "ximage"
	<li>MESA_GAMMA - gamma correction coefficients for red, green, blue channels
	<li>MESA_XSYNC - enable synchronous X behavior (for debugging only)
	<li>MESA_GLX_FORCE_CI - if set, force GLX to treat 8bpp visuals as CI visuals
	<li>MESA_GLX_FORCE_ALPHA - if set, forces RGB windows to have an alpha channel.
	<li>MESA_GLX_DEPTH_BITS - specifies default number of bits for depth buffer.
	<li>MESA_GLX_ALPHA_BITS - specifies default number of bits for alpha channel.
	</ul>


	<h2>i945/i965 driver environment variables (non-Gallium)</h2>

	<ul>
	<li>INTEL_STRICT_CONFORMANCE - if set to 1, enable sw fallbacks to improve
	OpenGL conformance. If set to 2, always use software rendering.
	<li>INTEL_NO_BLIT - if set, disable hardware-accelerated glBitmap,
	glCopyPixels, glDrawPixels.
	</ul>


	<h2>Radeon driver environment variables (radeon, r200, and r300g)</h2>

	<ul>
	<li>RADEON_NO_TCL - if set, disable hardware-accelerated Transform/Clip/Lighting.
	</ul>


	<h2>EGL environment variables</h2>

	<p>
	Mesa EGL supports different sets of environment variables. See the
	<a href="egl.html">Mesa EGL</a> page for the details.
	</p>


	<h2>Gallium environment variables</h2>

	<ul>
	<li>GALLIUM_LOG_FILE - specifies a file for logging all errors, warnings, etc.
	rather than stderr.
	<li>GALLIUM_PRINT_OPTIONS - if non-zero, print all the Gallium environment
	variables which are used, and their current values.
	<li>GALLIUM_NOSSE - if non-zero, do not use SSE runtime code generation for
	shader execution
	<li>GALLIUM_NOPPC - if non-zero, do not use PPC runtime code generation for
	shader execution
	<li>GALLIUM_DUMP_CPU - if non-zero, print information about the CPU on start-up
	<li>TGSI_PRINT_SANITY - if set, do extra sanity checking on TGSI shaders and
	print any errors to stderr.
	<LI>DRAW_FSE - ???
	<LI>DRAW_NO_FSE - ???
	<li>DRAW_USE_LLVM - if set to zero, the draw module will not use LLVM to execute
	shaders, vertex fetch, etc.
	</ul>

	<h3>Softpipe driver environment variables</h3>
	<ul>
	<li>SOFTPIPE_DUMP_FS - if set, the softpipe driver will print fragment shaders
	to stderr
	<li>SOFTPIPE_DUMP_GS - if set, the softpipe driver will print geometry shaders
	to stderr
	<li>SOFTPIPE_NO_RAST - if set, rasterization is no-op'd. For profiling purposes.
	<li>SOFTPIPE_USE_LLVM - if set, the softpipe driver will try to use LLVM JIT for
	vertex shading procesing.
	</ul>


	<h3>LLVMpipe driver environment variables</h3>
	<ul>
	<li>LP_NO_RAST - if set LLVMpipe will no-op rasterization
	<li>LP_DEBUG - a comma-separated list of debug options is acceptec. See the
	source code for details.
	<li>LP_PERF - a comma-separated list of options to selectively no-op various
	parts of the driver. See the source code for details.
	<li>LP_NUM_THREADS - an integer indicating how many threads to use for rendering.
	Zero turns of threading completely. The default value is the number of CPU
	cores present.
	</ul>


	<p>
	Other Gallium drivers have their own environment variables. These may change
	frequently so the source code should be consulted for details.
	</p>

	</body>
	</html>