Environment Variables
+Environment Variables
-Mesa supports the following environment variables: +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.
+ + +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 DRI drivers +
- LIBGL_ALWAYS_INDIRECT - if set to `true`, forces an indirect rendering context/connection. +
- LIBGL_ALWAYS_SOFTWARE - if set to `true`, always use software rendering +
- 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`. +
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_DEBUG - if set, error messages are printed to stderr. -If the value of MESA_DEBUG is "FP" floating point arithmetic errors will -generate exceptions. -
- MESA_NO_DITHER - if set, disables dithering, overriding glEnable(GL_DITHER) +
- 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 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: +-
+
- 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 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, warnings, +etc., rather than stderr
- 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 transformation @@ -28,12 +76,101 @@ 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_GLSL - shading language options +
- 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 + 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 + 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. +
- 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.
+
-
+
- 2.1 - select a compatibility (non-Core) profile with GL + version 2.1. +
- 3.0 - select a compatibility (non-Core) profile with GL + version 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 + 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 + enabled. +
- X.Y - override GL version to X.Y without changing the profile. +
- X.YFC - select a Core+Forward Compatible profile with GL + version X.Y. +
- X.YCOMPAT - select a Compatibility profile with GL version + X.Y. +
- 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.
+
-
+
- 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 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 shader cache +
- 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 +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 +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_shader_cache (if +that variable is set), or else within .cache/mesa_shader_cache within the user's +home directory. +
- MESA_GLSL - shading language compiler options +
- MESA_NO_MINMAX_CACHE - when set, the minmax index cache is globally disabled. +
- MESA_SHADER_CAPTURE_PATH - see Capturing Shaders +
- MESA_SHADER_DUMP_PATH and MESA_SHADER_READ_PATH - see Experimenting with Shader Replacements +
- 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 +
- This can be very useful for debugging but some features may not be + implemented correctly. (For developers only) +
Mesa Xlib driver environment variables
+-The following are only applicable to the Xlib software driver. -See the Xlib software driver page for details. +The following are only applicable to the Mesa Xlib software driver. +See the Xlib software driver page for details.
- MESA_RGB_VISUAL - specifies the X visual and depth for RGB mode @@ -43,32 +180,204 @@ See the Xlib software driver page for details.
- 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 visuals -
- MESA_GLX_FX - set to either "fullscreen" for full-screen rendering, - "window" to render into a window, or "disable" to disable the Glide driver.
- 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 buffer.
- MESA_GLX_ALPHA_BITS - specifies default number of bits for alpha channel.
-These environment variables are for the Intel i945/i965 drivers: -
+i945/i965 driver environment variables (non-Gallium)
+ +-
+
- 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 various things:
-
-
- INTEL_STRICT_CONFORMANCE - if set to 1, enable sw fallbacks to improve - OpenGL conformance. If set to 2, always use software rendering. -
- INTEL_NO_BLIT - if set, disable hardware-accelerated glBitmap, - glCopyPixels, glDrawPixels. +
- 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 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 debugging broken shaders +
- 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 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, 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 (useful to debug spilling code) +
- 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 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 shader stage (Gen8-9 only) +
- 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 Transform/Clip/Lighting. +
EGL environment variables
-These environment variables are for the Radeon R300 driver: +Mesa EGL supports different sets of environment variables. See the +Mesa EGL page for the details.
+ + +Gallium environment variables
+ +-
+
- 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). 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 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 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, warnings, etc. + rather than stderr. +
- 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 start-up +
- 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 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. +
Clover state tracker environment variables
+ +-
+
- 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 compiler + options. Specified options are appended after the options 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. +
Softpipe driver environment variables
+-
+
- 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 shaders + to stderr +
- 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 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 the + source code for details. +
- 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 rendering. + Zero turns off threading completely. The default value is the number of CPU + cores present. +
VMware SVGA driver environment variables
-
-
- R300_NO_TCL - if set, disable hardware-accelerated Transform/Clip/Lighting. +
- 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 code +for details. +
- 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.
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 effect. +
VA-API state tracker environment variables
+-
+
- 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 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) +
+Other Gallium drivers have their own environment variables. These may change +frequently so the source code should be consulted for details. +
- - +