4 Normally, no environment variables need to be set. Most of the
5 environment variables used by Mesa/Gallium are for debugging purposes,
6 but they can sometimes be useful for debugging end-user issues.
8 LibGL environment variables
9 ---------------------------
12 If defined debug information will be printed to stderr. If set to
13 ``verbose`` additional information will be printed.
14 ``LIBGL_DRIVERS_PATH``
15 colon-separated list of paths to search for DRI drivers
16 ``LIBGL_ALWAYS_INDIRECT``
17 if set to ``true``, forces an indirect rendering context/connection.
18 ``LIBGL_ALWAYS_SOFTWARE``
19 if set to ``true``, always use software rendering
20 ``LIBGL_NO_DRAWARRAYS``
21 if set to ``true``, do not use DrawArrays GLX protocol (for
24 print framerate to stdout based on the number of ``glXSwapBuffers``
26 ``LIBGL_DRI3_DISABLE``
27 disable DRI3 if set to ``true``.
29 Core Mesa environment variables
30 -------------------------------
33 if set, disables all assembly language optimizations
35 if set, disables Intel MMX optimizations
37 if set, disables AMD 3DNow! optimizations
39 if set, disables Intel SSE optimizations
41 if set to 1, error checking is disabled as per ``KHR_no_error``. This
42 will result in undefined behaviour for invalid use of the api, but
43 can reduce CPU use for apps that are known to be error free.
45 if set, error messages are printed to stderr. For example, if the
46 application generates a ``GL_INVALID_ENUM`` error, a corresponding
47 error message indicating where the error occurred, and possibly why,
48 will be printed to stderr. For release builds, ``MESA_DEBUG``
49 defaults to off (no debug output). ``MESA_DEBUG`` accepts the
50 following comma-separated list of named flags, which adds extra
51 behaviour to just set ``MESA_DEBUG=1``:
54 turn off debug messages. Only useful for debug builds.
56 flush after each drawing command
58 extra debug messages when a texture is incomplete
60 extra debug messages when a fbo is incomplete
62 create a debug context (see ``GLX_CONTEXT_DEBUG_BIT_ARB``) and
63 print error and performance messages to stderr (or
67 specifies a file name for logging all errors, warnings, etc., rather
70 if set, implement conventional texture env modes with fragment
71 programs (intended for developers only)
73 if set, implement conventional vertex transformation operations with
74 vertex programs (intended for developers only). Setting this variable
75 automatically sets the ``MESA_TEX_PROG`` variable as well.
76 ``MESA_EXTENSION_OVERRIDE``
77 can be used to enable/disable extensions. A value such as
78 ``GL_EXT_foo -GL_EXT_bar`` will enable the ``GL_EXT_foo`` extension
79 and disable the ``GL_EXT_bar`` extension.
80 ``MESA_EXTENSION_MAX_YEAR``
81 The ``GL_EXTENSIONS`` string returned by Mesa is sorted by extension
82 year. If this variable is set to year X, only extensions defined on
83 or before year X will be reported. This is to work-around a bug in
84 some games where the extension string is copied into a fixed-size
85 buffer without truncating. If the extension string is too long, the
86 buffer overrun can cause the game to crash. This is a work-around for
88 ``MESA_GL_VERSION_OVERRIDE``
89 changes the value returned by ``glGetString(GL_VERSION)`` and
90 possibly the GL API type.
92 - The format should be ``MAJOR.MINOR[FC|COMPAT]``
93 - ``FC`` is an optional suffix that indicates a forward compatible
94 context. This is only valid for versions >= 3.0.
95 - ``COMPAT`` is an optional suffix that indicates a compatibility
96 context or ``GL_ARB_compatibility`` support. This is only valid
98 - GL versions <= 3.0 are set to a compatibility (non-Core) profile
99 - GL versions = 3.1, depending on the driver, it may or may not have
100 the ``ARB_compatibility`` extension enabled.
101 - GL versions >= 3.2 are set to a Core profile
105 select a compatibility (non-Core) profile with GL version 2.1.
107 select a compatibility (non-Core) profile with GL version 3.0.
109 select a Core+Forward Compatible profile with GL version 3.0.
111 select GL version 3.1 with ``GL_ARB_compatibility`` enabled per
114 select GL version 3.1 with forward compatibility and
115 ``GL_ARB_compatibility`` disabled.
117 select GL version 3.1 with ``GL_ARB_compatibility`` enabled.
119 override GL version to X.Y without changing the profile.
121 select a Core+Forward Compatible profile with GL version X.Y.
123 select a Compatibility profile with GL version X.Y.
125 - Mesa may not really implement all the features of the given
126 version. (for developers only)
128 ``MESA_GLES_VERSION_OVERRIDE``
129 changes the value returned by ``glGetString(GL_VERSION)`` for OpenGL
132 - The format should be ``MAJOR.MINOR``
133 - Examples: ``2.0``, ``3.0``, ``3.1``
134 - Mesa may not really implement all the features of the given
135 version. (for developers only)
137 ``MESA_GLSL_VERSION_OVERRIDE``
138 changes the value returned by
139 ``glGetString(GL_SHADING_LANGUAGE_VERSION)``. Valid values are
140 integers, such as ``130``. Mesa will not really implement all the
141 features of the given language version if it's higher than what's
142 normally reported. (for developers only)
143 ``MESA_GLSL_CACHE_DISABLE``
144 if set to ``true``, disables the GLSL shader cache
145 ``MESA_GLSL_CACHE_MAX_SIZE``
146 if set, determines the maximum size of the on-disk cache of compiled
147 GLSL programs. Should be set to a number optionally followed by
148 ``K``, ``M``, or ``G`` to specify a size in kilobytes, megabytes, or
149 gigabytes. By default, gigabytes will be assumed. And if unset, a
150 maximum size of 1GB will be used.
154 A separate cache might be created for each architecture that Mesa is
155 installed for on your system. For example under the default settings
156 you may end up with a 1GB cache for x86_64 and another 1GB cache for
159 ``MESA_GLSL_CACHE_DIR``
160 if set, determines the directory to be used for the on-disk cache of
161 compiled GLSL programs. If this variable is not set, then the cache
162 will be stored in ``$XDG_CACHE_HOME/mesa_shader_cache`` (if that
163 variable is set), or else within ``.cache/mesa_shader_cache`` within
164 the user's home directory.
166 :ref:`shading language compiler options <envvars>`
167 ``MESA_NO_MINMAX_CACHE``
168 when set, the minmax index cache is globally disabled.
169 ``MESA_SHADER_CAPTURE_PATH``
170 see :ref:`Capturing Shaders <capture>`
171 ``MESA_SHADER_DUMP_PATH`` and ``MESA_SHADER_READ_PATH``
172 see :ref:`Experimenting with Shader
173 Replacements <replacement>`
174 ``MESA_VK_VERSION_OVERRIDE``
175 changes the Vulkan physical device version as returned in
176 ``VkPhysicalDeviceProperties::apiVersion``.
178 - The format should be ``MAJOR.MINOR[.PATCH]``
179 - This will not let you force a version higher than the driver's
180 instance version as advertised by ``vkEnumerateInstanceVersion``
181 - This can be very useful for debugging but some features may not be
182 implemented correctly. (For developers only)
184 NIR passes environment variables
185 --------------------------------
187 The following are only applicable for drivers that uses NIR, as they
188 modify the behaviour for the common NIR_PASS and NIR_PASS_V macros, that
189 wrap calls to NIR lowering/optimizations.
192 If defined, the resulting NIR shader will be printed out at each
193 successful NIR lowering/optimization call.
195 If defined, cloning a NIR shader would be tested at each successful
196 NIR lowering/optimization call.
197 ``NIR_TEST_SERIALIZE``
198 If defined, serialize and deserialize a NIR shader would be tested at
199 each successful NIR lowering/optimization call.
201 Mesa Xlib driver environment variables
202 --------------------------------------
204 The following are only applicable to the Mesa Xlib software driver. See
205 the :doc:`Xlib software driver page <xlibdriver>` for details.
208 specifies the X visual and depth for RGB mode
210 specifies the X visual and depth for CI mode
212 specifies how to implement the back color buffer, either ``pixmap``
215 gamma correction coefficients for red, green, blue channels
217 enable synchronous X behavior (for debugging only)
218 ``MESA_GLX_FORCE_CI``
219 if set, force GLX to treat 8bpp visuals as CI visuals
220 ``MESA_GLX_FORCE_ALPHA``
221 if set, forces RGB windows to have an alpha channel.
222 ``MESA_GLX_DEPTH_BITS``
223 specifies default number of bits for depth buffer.
224 ``MESA_GLX_ALPHA_BITS``
225 specifies default number of bits for alpha channel.
227 i945/i965 driver environment variables (non-Gallium)
228 ----------------------------------------------------
231 if set to 1, prevents batches from being submitted to the hardware.
232 This is useful for debugging hangs, etc.
234 a comma-separated list of named flags, which do various things:
237 annotate IR in assembly dumps
239 dump batches into an AUB trace for use with simulation tools
241 emit batch information
243 emit messages about blit operations
245 emit messages about the blorp operations (blits & clears)
247 emit messages about buffer objects
249 emit messages about the clip unit (for old gens, includes the CLIP
254 dump shader assembly for compute shaders
256 generate compute shader SIMD32 programs even if workgroup size
257 doesn't exceed the SIMD16 limit
259 emit messages about the DRI interface
261 emit messages about framebuffers
263 dump shader assembly for fragment shaders
265 dump shader assembly for geometry shaders
267 print instruction hex dump with the disassembly
269 emit messages about the new L3 state during transitions
271 emit messages about miptrees
273 don't generate SIMD8 fragment shader
275 suppress generation of 16-wide fragment shaders. useful for
276 debugging broken shaders
278 disable instruction compaction
280 suppress generation of dual-object geometry shader code
284 disable single sampled render buffer compression
286 dump shader assembly to files at each optimization pass and
287 iteration that make progress
289 emit messages about performance issues
291 emit messages about ``AMD_performance_monitor``
293 emit messages about pixel operations
295 emit messages about drawing primitives
297 mark all state dirty on each draw call
299 emit messages about the strips & fans unit (for old gens, includes
302 record how much GPU time is spent in each shader
304 force spilling of all registers in the scalar backend (useful to
307 force spilling of all registers in the vec4 backend (useful to
310 emit messages about state flag tracking
312 emit batchbuffer usage statistics
314 after sending each batch, emit a message and wait for that batch
317 dump shader assembly for tessellation control shaders
319 dump shader assembly for tessellation evaluation shaders
321 emit messages about textures.
323 emit messages about URB setup
325 emit messages about vertex assembly
327 dump shader assembly for vertex shaders
329 ``INTEL_SCALAR_VS`` (or ``TCS``, ``TES``, ``GS``)
330 force scalar/vec4 mode for a shader stage (Gen8-9 only)
331 ``INTEL_PRECISE_TRIG``
332 if set to 1, true or yes, then the driver prefers accuracy over
333 performance in trig functions.
335 Radeon driver environment variables (radeon, r200, and r300g)
336 -------------------------------------------------------------
339 if set, disable hardware-accelerated Transform/Clip/Lighting.
341 EGL environment variables
342 -------------------------
344 Mesa EGL supports different sets of environment variables. See the
345 :doc:`Mesa EGL <egl>` page for the details.
347 Gallium environment variables
348 -----------------------------
351 draws various information on the screen, like framerate, cpu load,
352 driver statistics, performance counters, etc. Set
353 ``GALLIUM_HUD=help`` and run e.g. ``glxgears`` for more info.
354 ``GALLIUM_HUD_PERIOD``
355 sets the hud update rate in seconds (float). Use zero to update every
356 frame. The default period is 1/2 second.
357 ``GALLIUM_HUD_VISIBLE``
358 control default visibility, defaults to true.
359 ``GALLIUM_HUD_TOGGLE_SIGNAL``
360 toggle visibility via user specified signal. Especially useful to
361 toggle hud at specific points of application and disable for
362 unencumbered viewing the rest of the time. For example, set
363 ``GALLIUM_HUD_VISIBLE`` to ``false`` and
364 ``GALLIUM_HUD_TOGGLE_SIGNAL`` to ``10`` (``SIGUSR1``). Use
365 ``kill -10 <pid>`` to toggle the hud as desired.
366 ``GALLIUM_HUD_SCALE``
367 Scale hud by an integer factor, for high DPI displays. Default is 1.
368 ``GALLIUM_HUD_DUMP_DIR``
369 specifies a directory for writing the displayed hud values into
372 useful in combination with ``LIBGL_ALWAYS_SOFTWARE=true`` for
373 choosing one of the software renderers ``softpipe``, ``llvmpipe`` or
376 specifies a file for logging all errors, warnings, etc. rather than
378 ``GALLIUM_PRINT_OPTIONS``
379 if non-zero, print all the Gallium environment variables which are
380 used, and their current values.
382 if non-zero, print information about the CPU on start-up
383 ``TGSI_PRINT_SANITY``
384 if set, do extra sanity checking on TGSI shaders and print any errors
391 if set to zero, the draw module will not use LLVM to execute shaders,
394 controls debug output from the Mesa/Gallium state tracker. Setting to
395 ``tgsi``, for example, will print all the TGSI shaders. See
396 ``src/mesa/state_tracker/st_debug.c`` for other options.
398 Clover environment variables
399 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
401 ``CLOVER_EXTRA_BUILD_OPTIONS``
402 allows specifying additional compiler and linker options. Specified
403 options are appended after the options set by the OpenCL program in
405 ``CLOVER_EXTRA_COMPILE_OPTIONS``
406 allows specifying additional compiler options. Specified options are
407 appended after the options set by the OpenCL program in
408 ``clCompileProgram``.
409 ``CLOVER_EXTRA_LINK_OPTIONS``
410 allows specifying additional linker options. Specified options are
411 appended after the options set by the OpenCL program in
414 Softpipe driver environment variables
415 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
418 a comma-separated list of named flags, which do various things:
421 Dump vertex shader assembly to stderr
423 Dump fragment shader assembly to stderr
425 Dump geometry shader assembly to stderr
427 Dump compute shader assembly to stderr
429 rasterization is no-op'd. For profiling purposes.
431 the softpipe driver will try to use LLVM JIT for vertex
434 LLVMpipe driver environment variables
435 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
438 if set LLVMpipe will no-op rasterization
440 a comma-separated list of debug options is accepted. See the source
443 a comma-separated list of options to selectively no-op various parts
444 of the driver. See the source code for details.
446 an integer indicating how many threads to use for rendering. Zero
447 turns off threading completely. The default value is the number of
450 VMware SVGA driver environment variables
451 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
454 force use of software vertex transformation
456 don't allow software vertex transformation fallbacks (will often
457 result in incorrect rendering).
459 for dumping shaders, constant buffers, etc. See the code for details.
460 ``SVGA_EXTRA_LOGGING``
461 if set, enables extra logging to the ``vmware.log`` file, such as the
462 OpenGL program's name and command line arguments.
464 if set, disables logging to the ``vmware.log`` file. This is useful
465 when using Valgrind because it otherwise crashes when initializing
466 the host log feature.
468 See the driver code for other, lesser-used variables.
470 WGL environment variables
471 ~~~~~~~~~~~~~~~~~~~~~~~~~
473 ``WGL_SWAP_INTERVAL``
474 to set a swap interval, equivalent to calling
475 ``wglSwapIntervalEXT()`` in an application. If this environment
476 variable is set, application calls to ``wglSwapIntervalEXT()`` will
479 VA-API environment variables
480 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
482 ``VAAPI_MPEG4_ENABLED``
483 enable MPEG4 for VA-API, disabled by default.
485 VC4 driver environment variables
486 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
489 a comma-separated list of named flags, which do various things:
492 dump command list during creation
494 dump generated QPU instructions
496 dump QPU IR during program compile
498 dump NIR during program compile
500 dump TGSI during program compile
502 dump program compile information for shader-db analysis
504 print during performance-related events
506 skip actual hardware execution of commands
508 flush after each draw call
510 wait for finish after each flush
512 write a GPU command stream trace file (VC4 simulator only)
514 RADV driver environment variables
515 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
518 a comma-separated list of named flags, which do various things:
521 enable LLVM compiler backend
523 force all allocated buffers to be referenced in submissions
525 enable all device/instance entrypoints
527 validate the LLVM IR before LLVM compiles the shader
529 display more info about errors
531 show GPU-related information
533 dump internal meta shaders
535 disable primitive binning
537 disable shaders cache
539 disable compute queue
541 disable Delta Color Compression (DCC) on images
543 do not check OOB access for dynamic descriptors
545 disable fast color/depthstencil clears
547 disable HIZ for depthstencil images
549 disable directly recording command buffers in GPU-visible memory
551 disable memory shaders cache
553 disable NGG for GFX10+
555 disable out-of-order rasterization
557 disable LLVM threaded compilation
559 dump LLVM IR before any optimizations
563 dump shader statistics
567 display info at startup
569 synchronize shaders after all draws/dispatches
571 check for VM memory faults via dmesg
573 initialize all memory allocated in VRAM as zero
575 ``RADV_FORCE_FAMILY``
576 create a null device to compile shaders without a AMD GPU (eg.
579 a comma-separated list of named flags, which do various things:
582 enable the global BO list
584 enable wave32 for compute shaders (GFX10+)
586 enable DCC for MSAA images
590 enable wave32 for vertex/tess/geometry shaders (GFX10+)
594 enable wave32 for pixel shaders (GFX10+)
596 enable TC-compat cmask for MSAA images
599 force anisotropy filter (up to 16)
601 generate cmdbuffer tracefiles when a GPU hang is detected
603 a comma-separated list of named flags, which do various things:
606 validate the ACO IR at various points of compilation (enabled by
607 default for debug/debugoptimized builds)
609 validate register assignment of ACO IR and catches many RA bugs
611 abort on some suboptimal code generation
613 radeonsi driver environment variables
614 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
617 a comma-separated list of named flags, which do various things:
623 Disable SDMA image copies
625 Clear VRAM allocations.
629 Disable DCC fast clear.
631 Disable separate DCC on the main framebuffer
641 Disable MSAA compression
649 Print driver information
655 Print virtual addresses when creating resources
661 Print geometry shaders
663 Print tessellation control shaders
665 Print tessellation evaluation shaders
667 Print compute shaders
669 Don't print the LLVM IR
671 Don't print NIR when printing shaders
673 Don't print disassembled shaders
675 Print the LLVM IR before initial optimizations
677 Enable LLVM global instruction selector.
679 Use Wave32 for vertex, tessellation, and geometry shaders.
681 Use Wave32 for pixel shaders.
683 Use Wave32 for computes shaders.
685 Use Wave64 for vertex, tessellation, and geometry shaders.
687 Use Wave64 for pixel shaders.
689 Use Wave64 for computes shaders.
691 Enable additional sanity checks on shader IR
693 Use old-style monolithic shaders compiled on demand
695 Disable compiling optimized shader variants.
697 Use SDMA for all operations when possible.
699 Disable GTT write combining
701 Check VM faults and dump debug info.
703 Force VMID reservation per context.
705 Disable graphics. Only multimedia compute paths can be used.
707 Disable NGG and use the legacy pipeline.
709 Always use NGG culling even when it can hurt.
713 Always enable the primitive discard compute shader.
715 Enable the primitive discard compute shader for large draw calls.
717 Disable the primitive discard compute shader.
719 Program WD/IA to switch on end-of-packet.
721 Disable out-of-order rasterization
727 Other Gallium drivers have their own environment variables. These may
728 change frequently so the source code should be consulted for details.