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_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_DRI2_DISABLE¶: disable DRI2 if set to true.

LIBGL_DRI3_DISABLE¶: disable DRI3 if set to true.

LIBGL_KOPPER_DISABLE¶: disable Vulkan swapchains with Zink if set to true. In general, this should not be used unless you know what you are doing. Some examples of “knowing what you are doing” include: - using a VK driver which has no WSI implementation for your display server - profiling the DRI frontend against your VK driver’s WSI implementation

LIBGL_KOPPER_DRI2¶: disable DRI3 with Zink if set to true. In general, this should not be used unless you know what you are doing. Some examples of “knowing what you are doing” include: - running xrdp - using a VK driver which doesn’t support modifiers

Core Mesa environment variables¶

MESA_NO_ERROR¶: if set to 1, error checking is disabled as per GL_KHR_no_error. This will result in undefined behavior 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 behavior to just set MESA_DEBUG to 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_PROCESS_NAME¶: if set, overrides the process name string used internally for various purposes (e.g. for driconf option matching, logging, artifact storage, etc.).

MESA_LOG_FILE¶: specifies a file name for logging all errors, warnings, etc., rather than stderr

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. Note that this will override extensions override configured using driconf.

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 GL_ARB_compatibility extension enabled.
GL versions >= 3.2 are set to a Core profile
Examples:

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_DRICONF_EXECUTABLE_OVERRIDE¶: if set, overrides the “executable” string used specifically for driconf option matching. This takes higher precedence over more general process name override (e.g. MESA_PROCESS_NAME).

MESA_SHADER_CACHE_DISABLE¶: if set to true, disables the on-disk shader cache. If set to false, enables the on-disk shader cache when it is disabled by default. Note that EGL_ANDROID_blob_cache is still enabled even if on-disk shader cache is disabled.

MESA_SHADER_CACHE_MAX_SIZE¶: if set, determines the maximum size of the on-disk cache of compiled shader 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_SHADER_CACHE_DIR¶: if set, determines the directory to be used for the on-disk cache of compiled shader programs. If this variable is not set, then the cache will be stored in $XDG_CACHE_HOME/mesa_shader_cache_db (if that variable is set), or else within .cache/mesa_shader_cache_db within the user’s home directory.

MESA_SHADER_CACHE_SHOW_STATS¶: if set to true, keeps hit/miss statistics for the shader cache. These statistics are printed when the app terminates.

MESA_DISK_CACHE_SINGLE_FILE¶: if set to 1, enables the single file Fossilize DB on-disk shader cache implementation instead of the default Mesa-DB cache implementation. This implementation allows for loading of precompiled cache DBs via MESA_DISK_CACHE_READ_ONLY_FOZ_DBS or MESA_DISK_CACHE_READ_ONLY_FOZ_DBS_DYNAMIC_LIST. This implementation does not support cache size limits via MESA_SHADER_CACHE_MAX_SIZE. If MESA_SHADER_CACHE_DIR is not set, the cache will be stored in $XDG_CACHE_HOME/mesa_shader_cache_sf (if that variable is set) or else within .cache/mesa_shader_cache_sf within the user’s home directory.

MESA_DISK_CACHE_MULTI_FILE¶: if set to 1, enables the multi file on-disk shader cache implementation instead of the default Mesa-DB cache implementation. This implementation increases the overall disk usage. If MESA_SHADER_CACHE_DIR is not set, 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_DISK_CACHE_READ_ONLY_FOZ_DBS¶: if set with MESA_DISK_CACHE_SINGLE_FILE enabled, references a string of comma separated file paths to read only Fossilize DB shader caches for loading at initialization. The file paths are relative to the cache directory and do not include suffixes, referencing both the cache DB and its index file. E.g. MESA_DISK_CACHE_SINGLE_FILE=filename1 refers to filename1.foz and filename1_idx.foz. A limit of 8 DBs can be loaded and this limit is shared with MESA_DISK_CACHE_READ_ONLY_FOZ_DBS_DYNAMIC_LIST.

MESA_DISK_CACHE_DATABASE_NUM_PARTS¶: specifies number of mesa-db cache parts, default is 50.

MESA_DISK_CACHE_DATABASE_EVICTION_SCORE_2X_PERIOD¶: Mesa-DB cache eviction algorithm calculates weighted score for the cache items. The weight is doubled based on the last access time of cache entry. By default period of weight doubling is set to one month. Period value is given in seconds.

MESA_DISK_CACHE_READ_ONLY_FOZ_DBS_DYNAMIC_LIST¶: if set with MESA_DISK_CACHE_SINGLE_FILE enabled, references a text file that contains a new-line separated list of read only Fossilize DB shader caches to load. The list file is modifiable at runtime to allow for loading read only caches after initialization unlike MESA_DISK_CACHE_READ_ONLY_FOZ_DBS. This variable takes an absolute path to the list file. The list file must exist at initialization for updating to occur. Cache files in the list take relative paths to the current cache directory like MESA_DISK_CACHE_READ_ONLY_FOZ_DBS. A limit of 8 DBs can be loaded and this limit is shared with MESA_DISK_CACHE_READ_ONLY_FOZ_DBS.

MESA_DISK_CACHE_COMBINE_RW_WITH_RO_FOZ¶: if set to 1, enables simultaneous use of RW and RW Fossilize DB caches. At first, data will be retrieved from the RO Fossilize cache. If data isn’t found in the RO cache, then it will be retrieved from the RW cache.

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¶: see Experimenting with Shader Replacements

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 version as advertised by vkEnumerateInstanceVersion
This can be very useful for debugging but some features may not be implemented correctly. (For developers only)

MESA_VK_WSI_PRESENT_MODE¶: overrides the WSI present mode clients specify in VkSwapchainCreateInfoKHR::presentMode. Values can be fifo, relaxed, mailbox or immediate.

MESA_VK_WSI_HEADLESS_SWAPCHAIN¶: Forces all swapchains to be headless (no rendering will be display in the swapchain’s window).

MESA_VK_ABORT_ON_DEVICE_LOSS¶: causes the Vulkan driver to call abort() immediately after detecting a lost device. This is extremely useful when testing as it prevents the test suite from continuing on with a lost device.

MESA_VK_ENABLE_SUBMIT_THREAD¶: for Vulkan drivers which support real timeline semaphores, this forces them to use a submit thread from the beginning, regardless of whether or not they ever see a wait-before-signal condition.

MESA_VK_DEVICE_SELECT_DEBUG¶: print debug info about device selection decision-making

MESA_VK_TRACE¶

A comma-separated list of trace types used for offline analysis. The option names are equal to the file extension. Traces are dumped into /tmp. Captures can be triggered by pressing F1 with the application window focused (Currently X11 only) or via MESA_VK_TRACE_FRAME and MESA_VK_TRACE_TRIGGER.

File extension	Offline analysis tool	Supported drivers
`rmv`	Radeon Memory Visualizer	`RADV`
`rgp`	Radeon GPU Profiler	`RADV`
`rra`	Radeon Raytracing Analyzer	`RADV`
`ctxroll`	Context rolls	`RADV`

Creating RMV captures requires the scripts/setup.sh script in the Radeon Developer Tools folder to be run beforehand

MESA_VK_TRACE_FRAME¶: Specifies a frame index at which a trace capture is automatically triggered.

MESA_VK_TRACE_TRIGGER¶: Specifies a trigger file. Creating the file triggers the capture. (e.g. export MESA_VK_TRACE_TRIGGER=/tmp/trigger and then touch /tmp/trigger)

MESA_LOADER_DRIVER_OVERRIDE¶: chooses a different driver binary such as etnaviv or zink.

DRI_PRIME_DEBUG¶: print debug info about device selection decision-making

DRI_PRIME¶

the default GPU is the one used by Wayland/Xorg or the one connected to a display. This variable allows to select a different GPU. It applies to OpenGL and Vulkan (in this case “select” means the GPU will be first in the reported physical devices list). The supported syntaxes are:

DRI_PRIME=N: selects the Nth non-default GPU (N > 0).
DRI_PRIME=pci-0000_02_00_0: selects the GPU connected to this PCIe bus
DRI_PRIME=vendor_id:device_id: selects the first GPU matching these ids.

For Vulkan it’s possible to append !, in which case only the selected GPU will be exposed to the application (e.g.: DRI_PRIME=1!).

Note

lspci -nn | grep VGA can be used to know the PCIe bus or ids to use.

DRIRC_CONFIGDIR¶: If set, overrides the global search-directories used when searching for drirc config files. The user-local one will still be used. Mostly useful for internal debugging.

NIR passes environment variables¶

The following are only applicable for drivers that uses NIR, as they modify the behavior for the common NIR_PASS and NIR_PASS_V macros, that wrap calls to NIR lowering/optimizations.

NIR_DEBUG¶: a comma-separated list of debug options to apply to NIR shaders. Use NIR_DEBUG=help to print a list of available options.

NIR_SKIP¶: a comma-separated list of optimization/lowering passes to skip.

Mesa Xlib driver environment variables¶

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

MESA_BACK_BUFFER¶: specifies how to implement the back color buffer, either pixmap or ximage

MESA_XSYNC¶: enable synchronous X behavior (for debugging only)

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.

Mesa WGL driver environment variables¶

The following are only applicable to the Mesa WGL driver, which is in use on Windows.

WGL_FORCE_MSAA¶: if set to a positive value, specifies the number of MSAA samples to force when choosing the display configuration.

WGL_DISABLE_ERROR_DIALOGS¶: if set to 1, true or yes, disables Win32 error dialogs. Useful for automated test-runs.

Intel driver environment variables¶

INTEL_BLACKHOLE_DEFAULT¶: if set to 1, true or yes, then the OpenGL implementation will default GL_BLACKHOLE_RENDER_INTEL to true, thus disabling any rendering.

INTEL_DEBUG¶

a comma-separated list of named flags, which do various things:

ann: annotate IR in assembly dumps
bat: emit batch information. Can control in which frames batches get dumped using INTEL_DEBUG_BATCH_FRAME_*, where INTEL_DEBUG_BATCH_FRAME_START <= frame < INTEL_DEBUG_BATCH_FRAME_STOP
blit: emit messages about blit operations
blorp: emit messages about the blorp operations (blits & clears)
buf: emit messages about buffer objects
bt: emit messages binding tables
capture-all: flag all buffers to be captured by the kernel driver when generating an error stage after a GPU hang
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
draw_bkp: Add semaphore wait before/after draw call count. INTEL_DEBUG_BKP_BEFORE_DRAW_COUNT or INTEL_DEBUG_BKP_AFTER_DRAW_COUNT can control draw call number. To make test wait forever, we need to set preempt_timeout_ms and i915.enable_hangcheck to zero.
fall: emit messages about performance issues (same as perf)
fs: dump shader assembly for fragment shaders
gs: dump shader assembly for geometry shaders
heaps: print information about the driver’s heaps (ANV only)
hex: print instruction hex dump with the disassembly
l3: emit messages about the new L3 state during transitions
mesh: dump shader assembly for mesh shaders
no8: don’t generate SIMD8 fragment shader
no16: suppress generation of 16-wide fragment shaders. useful for debugging broken shaders
no32: suppress generation of 32-wide fragment shaders. useful for debugging broken shaders
no-oaconfig: disable HW performance metric configuration, and anything related to i915-perf (useful when running on simulation)
nocompact: disable instruction compaction
nodualobj: suppress generation of dual-object geometry shader code
nofc: disable fast clears
noccs: disable lossless color compression
optimizer: dump shader assembly to files at each optimization pass and iteration that make progress
pc: emit messages about PIPE_CONTROL instruction usage
perf: emit messages about performance issues
perfmon: emit messages about GL_AMD_performance_monitor
perf-symbol-names: use performance counter symbols instead of the counter name (counter symbols are like variable names, it’s sometimes easier to work with when you have lots of metrics to collect)
reemit: mark all state dirty on each draw call
rt: dump shader assembly for ray tracing shaders
sf: emit messages about the strips & fans unit (for old gens, includes the SF program)
shader-print: allow developer print traces added by brw_nir_printf to be printed out on the console
soft64: enable implementation of software 64bit floating point support
sparse: dump usage of sparse resources
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)
stall: inserts a stall on the GPU after each draw/dispatch command to wait for it to finish before starting any new work.
submit: emit batchbuffer usage statistics
sync: after sending each batch, wait on the CPU for that batch to finish rendering
swsb-stall: Insert sync NOP after each instruction. This is only valid for Gfx12+.
task: dump shader assembly for task shaders
tcs: dump shader assembly for tessellation control shaders
tcs8: force usage of 8-patches tessellation control shaders (only for gfx 9-11)
tes: dump shader assembly for tessellation evaluation shaders
tex: emit messages about textures.
urb: emit messages about URB setup
vs: dump shader assembly for vertex shaders
wm: dump shader assembly for fragment shaders (same as fs)
cl-quiet: quiets the OpenCL warnings recommending use of Intel compute-runtime

INTEL_DECODE¶

a comma-separated list of enable/disable flags configuring the output produced by INTEL_DEBUG=bat (use with INTEL_DECODE=+color,-floats) :

color: print colored output
floats: try to decode floating point data in buffers
full: print additional custom information for instructions (usually pulling more information by inspecting memory)
offsets: print offsets of instructions

INTEL_EXTENDED_METRICS¶: By default, only a standard set of GPU metrics are advertised. This reduces time to collect metrics and hides infrequently used metrics. To enable all metrics, set value to 1.

INTEL_FORCE_PROBE¶

A comma-separated list of device probe override values. The basic format is <pci-id>[,<pci-id>,...]. The wildcard value of * will specify all known PCI IDs. If ! precedes a PCI ID, or the wildcard value, then the device support will be disabled. All numbers are interpreted in base 16, and a 0x prefix is optional. Values specified later take precedence, so the wildcard probably should only be used at the beginning.

Some examples :

1234,!abcd: Device 0x1234 would be forced on and 0xabcd would be disabled.
1234,!*: All devices are disabled since the wildcard appears later.
!*,0x1234: All devices disabled except 0x1234 which is forced on.
*,!0x1234: All devices are forced on, except 0x1234 which is disabled.
!0x1234,1234: Support for device 0x1234 is forced on since the enable appears later.

Note

If a device requires using INTEL_FORCE_PROBE to force it to load, then Mesa does not have full support for the device. It may have limited, or possibly no functionality within Mesa at this point. It is recommended to upgrade to a Mesa which does not require INTEL_FORCE_PROBE for the device as soon as it is available.

INTEL_MEASURE¶

Collects GPU timestamps over common intervals, and generates a CSV report to show how long rendering took. The overhead of collection is limited to the flushing that is required at the interval boundaries for accurate timestamps. By default, timing data is sent to stderr. To direct output to a file:

INTEL_MEASURE=file=/tmp/measure.csv {workload}

To begin capturing timestamps at a particular frame:

INTEL_MEASURE=file=/tmp/measure.csv,start=15 {workload}

To capture only 23 frames:

INTEL_MEASURE=count=23 {workload}

To capture frames 15-37, stopping before frame 38:

INTEL_MEASURE=start=15,count=23 {workload}

Designate an asynchronous control file with:

INTEL_MEASURE=control=path/to/control.fifo {workload}

As the workload runs, enable capture for 5 frames with:

$ echo 5 > path/to/control.fifo

Enable unbounded capture:

$ echo -1 > path/to/control.fifo

and disable with:

$ echo 0 > path/to/control.fifo

Select the boundaries of each snapshot with:

INTEL_MEASURE=draw: Collects timings for every render (DEFAULT)
INTEL_MEASURE=rt: Collects timings when the render target changes
INTEL_MEASURE=batch: Collects timings when batches are submitted
INTEL_MEASURE=frame: Collects timings at frame boundaries

With INTEL_MEASURE=interval=5, the duration of 5 events will be combined into a single record in the output. When possible, a single start and end event will be submitted to the GPU to minimize stalling. Combined events will not span batches, except in the case of INTEL_MEASURE=frame.

Collect CPU timestamps instead of GPU timestamps. Prints results immediately instead of waiting for GPU execution. Useful when used with interactive debug to know which frame, or where in frame, you are currently in.

INTEL_MEASURE=cpu {workload}

INTEL_MODIFIER_OVERRIDE¶: if set, determines the single DRM modifier reported back to (Vulkan) applications, in order to make selecting modifier deterministic between Vulkan driver and applications. The value can be one of the supported modifiers on a platform, but other values are also acceptable for debug purposes.

INTEL_NO_HW¶: if set to 1, true or yes, prevents batches from being submitted to the hardware. This is useful for debugging hangs, etc.

INTEL_PRECISE_TRIG¶: if set to 1, true or yes, then the driver prefers accuracy over performance in trig functions.

INTEL_SHADER_OPTIMIZER_PATH¶: if set, determines the directory to be used for overriding shader assembly. The binaries with custom assembly should be placed in this folder and have a name formatted as sha1_of_assembly.bin. The SHA-1 of a shader assembly is printed when assembly is dumped via corresponding INTEL_DEBUG flag (e.g. vs for vertex shader). A binary could be generated from a dumped assembly by i965_asm. For INTEL_SHADER_ASM_READ_PATH to work it is necessary to enable dumping of corresponding shader stages via INTEL_DEBUG. It is advised to use nocompact flag of INTEL_DEBUG when dumping and overriding shader assemblies. The success of assembly override would be signified by “Successfully overrode shader with sha1 <SHA-1>” in stderr replacing the original assembly.

INTEL_SHADER_ASM_READ_PATH¶: if set, determines the directory to be used for overriding shader assembly. The binaries with custom assembly should be placed in this folder and have a name formatted as sha1_of_assembly.bin. The SHA-1 of a shader assembly is printed when assembly is dumped via corresponding INTEL_DEBUG flag (e.g. vs for vertex shader). A binary could be generated from a dumped assembly by i965_asm. For INTEL_SHADER_ASM_READ_PATH to work it is necessary to enable dumping of corresponding shader stages via INTEL_DEBUG. It is advised to use nocompact flag of INTEL_DEBUG when dumping and overriding shader assemblies. The success of assembly override would be signified by “Successfully overrode shader with sha1 <SHA-1>” in stderr replacing the original assembly.

INTEL_SHADER_BIN_DUMP_PATH¶: if set, determines the directory to which the compiled shaders will be dumped. They will be dumped as sha1_of_assembly.bin, where the sha1 values will be the same as can be found in the INTEL_DEBUG output, and can be used for INTEL_SHADER_ASM_READ_PATH input.

Note
Unlike the text form of shader dumping, INTEL_DEBUG does not affect on the list of shaders to dump. All generated shaders are always dumped if INTEL_SHADER_BIN_DUMP_PATH variable is set.

INTEL_SIMD_DEBUG¶

a comma-separated list of named flags, which control simd dispatch widths:

fs8: allow generation of SIMD8 fragment shader
fs16: allow generation of SIMD16 fragment shader
fs32: allow generation of SIMD32 fragment shader
cs8: allow generation of SIMD8 compute shader
cs16: allow generation of SIMD16 compute shader
cs32: allow generation of SIMD32 compute shader
ts8: allow generation of SIMD8 task shader
ts16: allow generation of SIMD16 task shader
ts32: allow generation of SIMD32 task shader
ms8: allow generation of SIMD8 mesh shader
ms16: allow generation of SIMD16 mesh shader
ms32: allow generation of SIMD32 mesh shader
rt8: allow generation of SIMD8 ray-tracing shader
rt16: allow generation of SIMD16 ray-tracing shader
rt32: allow generation of SIMD32 ray-tracing shader

If none of widths for particular shader stage was specified, then all widths are allowed.

Anvil(ANV) driver environment variables¶

ANV_ENABLE_PIPELINE_CACHE¶: If defined to 0 or false, this will disable pipeline caching, forcing ANV to reparse and recompile any VkShaderModule (SPIRV) it is given.

ANV_DISABLE_SECONDARY_CMD_BUFFER_CALLS¶: If defined to 1 or true, this will prevent usage of self modifying command buffers to implement vkCmdExecuteCommands. As a result of this, it will also disable VK_KHR_performance_query.

ANV_ALWAYS_BINDLESS¶: If defined to 1 or true, this forces all descriptor sets to use the internal Binding Model.

ANV_QUEUE_THREAD_DISABLE¶: If defined to 1 or true, this disables support for timeline semaphores.

ANV_USERSPACE_RELOCS¶: If defined to 1 or true, this forces ANV to always do kernel relocations in command buffers. This should only have an effect on hardware that doesn’t support soft-pinning (Ivybridge, Haswell, Cherryview).

ANV_PRIMITIVE_REPLICATION_MAX_VIEWS¶: Specifies up to how many view shaders can be lowered to handle VK_KHR_multiview. Beyond this number, multiview is implemented using instanced rendering. If unspecified, the value default to 2.

ANV_NO_GPL¶: If set to 1, true, or yes, then VK_EXT_graphics_pipeline_library will be disabled.

ANV_SPARSE¶: By default, the sparse resources feature is enabled. However, if set to 0, false, or no, it will be disabled. Platforms older than Tiger Lake do not support this feature.

ANV_SPARSE_USE_TRTT¶: On platforms supported by Xe KMD (Lunar Lake and newer) this parameter changes the implementation of sparse resources feature. For i915 there is no option, sparse resources is always implemented with TRTT.

DRI environment variables¶

DRI_NO_MSAA¶: disable MSAA for GLX/EGL MSAA visuals

Vulkan mesa device select layer environment variables¶

MESA_VK_DEVICE_SELECT¶: when set to “list” prints the list of devices. when set to “vid:did” number from PCI device. That PCI device is selected as default. The default device is returned as the first device in vkEnumeratePhysicalDevices API. Using “vid:did!” will have the same effect as using the MESA_VK_DEVICE_SELECT_FORCE_DEFAULT_DEVICE variable.

MESA_VK_DEVICE_SELECT_FORCE_DEFAULT_DEVICE¶: when set to 1, the device identified as default will be the only one returned in vkEnumeratePhysicalDevices API.

EGL environment variables¶

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 to 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_OPACITY¶: control background opacity as an integer percentage (1-100), defaults to 66%.

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_SCALE¶: Scale HUD by an integer factor, for high DPI displays. Default is 1.

GALLIUM_HUD_ROTATION¶: Rotate the HUD by an integer number of degrees, the specified value must be a multiple of 90. Default is 0.

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 or llvmpipe.

GALLIUM_LOG_FILE¶: specifies a file for logging all errors, warnings, etc. rather than stderr.

GALLIUM_PIPE_SEARCH_DIR¶: specifies an alternate search directory for pipe-loader which overrides the compile-time path based on the install location.

GALLIUM_PRINT_OPTIONS¶: if non-zero, print all the Gallium environment variables which are used, and their current values.

GALLIUM_TRACE¶: If set, this variable will cause the Trace output to be written to the specified file. Paths may be relative or absolute; relative paths are relative to the working directory. For example, setting it to “trace.xml” will cause the trace to be written to a file of the same name in the working directory.

GALLIUM_TRACE_TC¶: If enabled while Trace is active, this variable specifies that the threaded context should be traced for drivers which implement it. By default, the driver thread is traced, which will include any reordering of the command stream from threaded context.

GALLIUM_TRACE_TRIGGER¶: If set while Trace is active, this variable specifies a filename to monitor. Once the file exists (e.g., from the user running ‘touch /path/to/file’), a single frame will be recorded into the trace output. Paths may be relative or absolute; relative paths are relative to the working directory.

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¶: Enable fetch-shade-emit middle-end even though its not correct (e.g. for Softpipe)

DRAW_NO_FSE¶: Disable fetch-shade-emit middle-end even when it is correct

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.

GALLIUM_OVERRIDE_CPU_CAPS¶: Override CPU capabilities for LLVMpipe and Softpipe, possible values for x86: nosse sse sse2 sse3 ssse3 sse4.1 avx

Clover environment variables¶

CLOVER_DEVICE_TYPE¶: allows to overwrite the device type of devices. Possible values are accelerator, cpu, custom and gpu

CLOVER_DEVICE_VERSION_OVERRIDE¶: overwrites the auto detected OpenCL version of a device. Possible values: 1.0 1.1 1.2 2.0 2.1 2.2 3.0

CLOVER_DEVICE_CLC_VERSION_OVERRIDE¶: overwrites the auto detected CLC version. Possible values: 1.0 1.1 1.2 2.0 2.1 2.2 3.0

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.

IRIS_ENABLE_CLOVER¶: allows to enable experimental Clover NIR support with the iris driver if set to 1 or true.

Rusticl environment variables¶

RUSTICL_DEVICE_TYPE¶: allows to overwrite the device type of devices. Possible values are accelerator, cpu, custom and gpu

RUSTICL_CL_VERSION¶: overwrites the auto detected OpenCL version of all devices. Specified as major.minor.

RUSTICL_ENABLE¶

a comma-separated list of drivers to enable CL on. An optional list of comma-separated integers can be passed per driver to specify which devices to enable. Examples:

RUSTICL_ENABLE=iris (enables all iris devices)
RUSTICL_ENABLE=iris:1,radeonsi:0,2 (enables second iris and first and third radeonsi device)

Supported drivers (decent support with maybe a few conformance issues or bugs): iris, llvmpipe, nouveau, panfrost, radeonsi, Experimental drivers (unknown level of support, expect conformance issues or major bugs): r600

RUSTICL_FEATURES¶

a comma-separated list of features to enable. Those are disabled by default as they might not be stable enough or break OpenCL conformance.

fp16 enables OpenCL half support
fp64 enables OpenCL double support

RUSTICL_DEBUG¶

a comma-separated list of debug channels to enable.

allow_invalid_spirv disables validation of any input SPIR-V
clc dumps all OpenCL C source being compiled
nir dumps nirs in various compilation stages. Might print nothing if shader caching is
enabled.
no_reuse_context pipe_contexts are not recycled
no_variants disable kernel variants (e.g. specialized binaries for offsets == 0)
perf prints a warning when hitting slow paths once
perfspam same as perf, but doesn’t skip same warnings
program dumps compilation logs to stderr
sync waits on the GPU to complete after every event
validate validates any internally generated SPIR-Vs, e.g. through compiling OpenCL C code

RUSTICL_MAX_WORK_GROUPS¶: Limits the amount of threads per dimension in a work-group. Useful for splitting up long running tasks to increase responsiveness or to simulate the lowering of huge global sizes for testing.

clc environment variables¶

CLC_DEBUG¶

a comma-separated list of debug channels to enable.

dump_llvm Dumps all generated LLVM IRs
dump_spirv Dumps all compiled, linked and specialized SPIR-Vs
verbose Enable debug logging of clc code

Nine frontend environment variables¶

D3D_ALWAYS_SOFTWARE¶: an integer, which forces Nine to use the CPU instead of GPU acceleration.

NINE_DEBUG¶: a comma-separated list of named flags that do debugging things. Use NINE_DEBUG=help to print a list of available options.

NINE_FF_DUMP¶: a boolean, which dumps shaders generated by a fixed function (FF).

NINE_SHADER¶: a comma-separated list of named flags, which do alternate shader handling. Use NINE_SHADER=help to print a list of available options.

NINE_QUIRKS¶: a comma-separated list of named flags that do various things. Use NINE_DEBUG=help to print a list of available options.

Softpipe driver environment variables¶

SOFTPIPE_DEBUG¶

a comma-separated list of named flags, which do various things:

vs: Dump vertex shader assembly to stderr
fs: Dump fragment shader assembly to stderr
gs: Dump geometry shader assembly to stderr
cs: Dump compute shader assembly to stderr
no_rast: rasterization is disabled. For profiling purposes.
use_llvm: 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¶

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.

SVGA_NO_LOGGING¶: if set, disables logging to the vmware.log file. This is useful when using Valgrind because it otherwise crashes when initializing the host log feature.

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 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. Use VC4_DEBUG=help to print a list of available options.

V3D/V3DV driver environment variables¶

V3D_DEBUG¶: a comma-separated list of debug options. Use V3D_DEBUG=help to print a list of available options.

RADV driver environment variables¶

RADV_DEBUG¶

a comma-separated list of named flags, which do various things:

llvm: enable LLVM compiler backend
allbos: force all allocated buffers to be referenced in submissions
checkir: validate the LLVM IR before LLVM compiles the shader
dump_trap_handler: dump the trap handler shader
epilogs: dump fragment shader epilogs
extra_md: add extra information in bo metadata to help tools (umr)
forcecompress: Enables DCC,FMASK,CMASK,HTILE in situations where the driver supports it but normally does not deem it beneficial.
hang: enable GPU hangs detection and dump a report to $HOME/radv_dumps_<pid>_<time> if a GPU hang is detected
img: Print image info
info: show GPU-related information
invariantgeom: Mark geometry-affecting outputs as invariant. This works around a common class of application bugs appearing as flickering.
metashaders: dump internal meta shaders
noatocdithering: disable dithering for alpha to coverage
nobinning: disable primitive binning
nocache: disable shaders cache
nocompute: disable compute queue
nodcc: disable Delta Color Compression (DCC) on images
nodisplaydcc: disable Delta Color Compression (DCC) on displayable images
nodynamicbounds: do not check OOB access for dynamic descriptors
noeso: disable VK_EXT_shader_object
nofastclears: disable fast color/depthstencil clears
nofmask: disable FMASK compression on MSAA images (GFX6-GFX10.3)
nogpl: disable VK_EXT_graphics_pipeline_library
nohiz: disable HIZ for depthstencil images
noibs: disable directly recording command buffers in GPU-visible memory
nomeshshader: disable mesh shader support on GFX10.3+
nongg: disable NGG for GFX10 and GFX10.3
nonggc: disable NGG culling on GPUs where it’s enabled by default (GFX10.3 only).
nongg_gs: disable NGG GS for GFX10 and GFX10.3
nort: skip executing vkCmdTraceRays and ray queries (RT extensions will still be advertised)
notccompatcmask: disable TC-compat CMASK for MSAA surfaces
noumr: disable UMR dumps during GPU hang detection (only with RADV_DEBUG = hang)
novrsflatshading: disable VRS for flat shading (only on GFX10.3+)
preoptir: Dump backend IR (ACO or LLVM) before any optimizations.
prologs: dump vertex shader prologs
psocachestats: dump PSO cache stats (hits/misses) to verify precompilation of shaders
shaders: dump shaders
shaderstats: dump shader statistics
shadowregs: enable register shadowing
spirv: dump SPIR-V
splitfma: split application-provided fused multiply-add in geometry stages
startup: display info at startup
syncshaders: synchronize shaders after all draws/dispatches
zerovram: initialize all memory allocated in VRAM as zero
vs: Dump vertex shaders.
tcs: Dump tessellation control shaders.
tes: Dump tessellation evaluation shaders.
gs: Dump geometry shaders.
ps: Dump fragment shaders.
task: Dump task shaders.
mesh: Dump mesh shaders.
cs: Dump compute (and ray tracing) shaders.
nir: Dump NIR for selected shader stages.
ir: Dump backend IR (ACO or LLVM) for selected shader stages.
asm: Dump shader disassembly for selected shader stages.

RADV_FORCE_FAMILY¶: create a null device to compile shaders without a AMD GPU (e.g. VEGA10)

RADV_FORCE_VRS¶: allow to force per-pipeline vertex VRS rates on GFX10.3+. This is only forced for pipelines that don’t explicitly use VRS or flat shading. The supported values are 2x2, 1x2, 2x1 and 1x1. Only for testing purposes.

RADV_FORCE_VRS_CONFIG_FILE¶: similar to RADV_FORCE_VRS but allow to configure from a file. If present, this supersedes RADV_FORCE_VRS.

RADV_PERFTEST¶

a comma-separated list of named flags, which do various things:

bolist: enable the global BO list
cswave32: enable wave32 for compute shaders (GFX10+)
dccmsaa: enable DCC for MSAA images
dmashaders: upload shaders to invisible VRAM (might be useful for non-resizable BAR systems)
emulate_rt: forces ray-tracing to be emulated in software on GFX10_3+ and enables rt extensions with older hardware.
gewave32: enable wave32 for vertex/tess/geometry shaders (GFX10+)
localbos: enable local BOs
nggc: enable NGG culling on GPUs where it’s not enabled by default (GFX10.1 only).
nircache: cache per-stage NIR for graphics pipelines
nosam: disable optimizations that get enabled when all VRAM is CPU visible.
pswave32: enable wave32 for pixel shaders (GFX10+)
rtwave32: enable wave32 for ray tracing shaders (GFX11+)
rtwave64: enable wave64 for ray tracing shaders (GFX10-10.3)
sam: enable optimizations to move more driver internal objects to VRAM.
transfer_queue: enable experimental transfer queue support (GFX9+, not yet spec compliant)
video_decode: enable experimental video decoding support

RADV_TEX_ANISO¶: force anisotropy filter (up to 16)

RADV_THREAD_TRACE_BUFFER_SIZE¶: set the SQTT/RGP buffer size in bytes (default value is 32MiB, the buffer is automatically resized if too small)

RADV_THREAD_TRACE_CACHE_COUNTERS¶: enable/disable SQTT/RGP cache counters on GFX10+ (enabled by default)

RADV_THREAD_TRACE_INSTRUCTION_TIMING¶: enable/disable SQTT/RGP instruction timing (enabled by default)

RADV_THREAD_TRACE_QUEUE_EVENTS¶: enable/disable SQTT/RGP queue events (enabled by default)

RADV_TRAP_HANDLER¶: enable/disable the experimental trap handler for debugging GPU hangs on GFX8 (disabled by default)

RADV_TRAP_HANDLER_EXCP¶

a comma-separated list of named flags to configure the trap handler exceptions, see the list below:

mem_viol: enable memory violation exception
float_div_by_zero: enable floating point division by zero exception
float_overflow: enable floating point overflow exception
float_underflow: enable floating point underflow exception

RADV_RRA_TRACE_VALIDATE¶: enable validation of captured acceleration structures. Can be useful if RRA crashes upon opening a trace.

RADV_RRA_TRACE_HISTORY_SIZE¶: set the ray history buffer size when capturing RRA traces (default value is 100MiB, small buffers may result in incomplete traces)

RADV_RRA_TRACE_RESOLUTION_SCALE¶: decrease the resolution used for dumping the ray history resolution when capturing RRA traces. This allows for dumping every Nth invocation along each dispatch dimension.

RADV_PROFILE_PSTATE¶

choose the specific pstate to enter when using thread tracing or when acquiring the profiling lock for performance queries.

standard: force GPU clocks to an arbitrary fixed level
min_sclk: force the shader clock to its minimum level
min_mclk: force the memory clock to its minimum level
peak: force GPU clocks to their maximum level, this is the default value

ACO_DEBUG¶

a comma-separated list of named flags, which do various things:

validateir: validate the ACO IR at various points of compilation (enabled by default for debug/debugoptimized builds)
novalidateir: disable ACO IR validation in debug/debugoptimized builds
validatera: validate register assignment of ACO IR and catches many RA bugs
force-waitcnt: force emitting waitcnt states if there is something to wait for
force-waitdeps: force emitting waitcnt dependencies for debugging hazards on GFX10+
novn: disable value numbering
noopt: disable various optimizations
nosched: disable pre-RA, ILP and VOPD instruction scheduling
nosched-ilp: disable ILP instruction scheduling
nosched-vopd: disable VOPD instruction scheduling
perfinfo: print information used to calculate some pipeline statistics
liveinfo: print liveness and register demand information before scheduling

RadeonSI driver environment variables¶

radeonsi_no_infinite_interp¶: Kill PS with infinite interp coeff (might fix hangs)

radeonsi_clamp_div_by_zero¶: Clamp div by zero (x / 0 becomes FLT_MAX instead of NaN) (might fix rendering corruptions)

radeonsi_zerovram¶: Clear all allocated memory to 0 before usage (might fix rendering corruptions)

AMD_DEBUG¶

a comma-separated list of named flags, which do various things:

nodcc: Disable DCC.
nodccclear: Disable DCC fast clear
nodisplaydcc: disable Delta Color Compression (DCC) on displayable images
nodccmsaa: Disable DCC for MSAA
nodpbb: Disable DPBB. Overrules the dpbb enable option.
noefc: Disable hardware based encoder color format conversion
lowlatencyenc: Enable low latency encoding
notiling: Disable tiling
nofmask: Disable MSAA compression
nohyperz: Disable Hyper-Z
no2d: Disable 2D tiling
info: Print driver information
tex: Print texture info
compute: Print compute info
vm: Print virtual addresses when creating resources
vs: Print vertex shaders
ps: Print pixel shaders
gs: Print geometry shaders
tcs: Print tessellation control shaders
tes: Print tessellation evaluation shaders
cs: Print compute shaders
noir: Don’t print the LLVM IR
nonir: Don’t print NIR when printing shaders
noasm: Don’t print disassembled shaders
preoptir: Print the LLVM IR before initial optimizations
w32ge: Use Wave32 for vertex, tessellation, and geometry shaders.
w32ps: Use Wave32 for pixel shaders.
w32cs: Use Wave32 for computes shaders.
w64ge: Use Wave64 for vertex, tessellation, and geometry shaders.
w64ps: Use Wave64 for pixel shaders.
w64cs: Use Wave64 for computes shaders.
checkir: Enable additional sanity checks on shader IR
mono: Use old-style monolithic shaders compiled on demand
nooptvariant: Disable compiling optimized shader variants.
useaco: Use ACO as shader compiler when possible
nowc: Disable GTT write combining
check_vm: Check VM faults and dump debug info.
reserve_vmid: Force VMID reservation per context.
nongg: Disable NGG and use the legacy pipeline.
nggc: Always use NGG culling even on GPUs where it is disabled by default.
nonggc: Disable NGG culling.
switch_on_eop: Program WD/IA to switch on end-of-packet.
nooutoforder: Disable out-of-order rasterization
dpbb: Enable DPBB. Enable DPBB for gfx9 dGPU. Default enabled for gfx9 APU and >= gfx10.
extra_md: add extra information in bo metadata to help tools (umr)

r600 driver environment variables¶

R600_DEBUG¶

a comma-separated list of named flags, which do various things:

nocpdma: Disable CP DMA
nosb: Disable sb backend for graphics shaders
sbcl: Enable sb backend for compute shaders
sbdry: Don’t use optimized bytecode (just print the dumps)
sbstat: Print optimization statistics for shaders
sbdump: Print IR dumps after some optimization passes
sbnofallback: Abort on errors instead of fallback
sbdisasm: Use sb disassembler for shader dumps
sbsafemath: Disable unsafe math optimizations
nirsb: Enable NIR with SB optimizer
tex: Print texture info
nir: Enable experimental NIR shaders
compute: Print compute info
vm: Print virtual addresses when creating resources
info: Print driver information
fs: Print fetch shaders
vs: Print vertex shaders
gs: Print geometry shaders
ps: Print pixel shaders
cs: Print compute shaders
tcs: Print tessellation control shaders
tes: Print tessellation evaluation shaders
noir: Don’t print the LLVM IR
notgsi: Don’t print the TGSI
noasm: Don’t print disassembled shaders
preoptir: Print the LLVM IR before initial optimizations
checkir: Enable additional sanity checks on shader IR
nooptvariant: Disable compiling optimized shader variants.
testdma: Invoke SDMA tests and exit.
testvmfaultcp: Invoke a CP VM fault test and exit.
testvmfaultsdma: Invoke a SDMA VM fault test and exit.
testvmfaultshader: Invoke a shader VM fault test and exit.
nodma: Disable asynchronous DMA
nohyperz: Disable Hyper-Z
noinvalrange: Disable handling of INVALIDATE_RANGE map flags
no2d: Disable 2D tiling
notiling: Disable tiling
switch_on_eop: Program WD/IA to switch on end-of-packet.
forcedma: Use asynchronous DMA for all operations when possible.
precompile: Compile one shader variant at shader creation.
nowc: Disable GTT write combining
check_vm: Check VM faults and dump debug info.
unsafemath: Enable unsafe math shader optimizations

R600_DEBUG_COMPUTE¶: if set to true, various compute-related debug information will be printed to stderr. Defaults to false.

R600_DUMP_SHADERS¶: if set to true, NIR shaders will be printed to stderr. Defaults to false.

R600_HYPERZ¶: If set to false, disables HyperZ optimizations. Defaults to true.

R600_NIR_DEBUG¶

a comma-separated list of named flags, which do various things:

instr: Log all consumed nir instructions
ir: Log created R600 IR
cc: Log R600 IR to assembly code creation
noerr: Don’t log shader conversion errors
si: Log shader info (non-zero values)
reg: Log register allocation and lookup
io: Log shader in and output
ass: Log IR to assembly conversion
flow: Log control flow instructions
merge: Log register merge operations
nomerge: Skip register merge step
tex: Log texture ops
trans: Log generic translation messages

r300 driver environment variables¶

RADEON_DEBUG¶

a comma-separated list of named flags, which do various things:

info: Print hardware info (printed by default on debug builds
fp: Log fragment program compilation
vp: Log vertex program compilation
draw: Log draw calls
swtcl: Log SWTCL-specific info
rsblock: Log rasterizer registers
psc: Log vertex stream registers
tex: Log basic info about textures
texalloc: Log texture mipmap tree info
rs: Log rasterizer
fb: Log framebuffer
cbzb: Log fast color clear info
hyperz: Log HyperZ info
scissor: Log scissor info
msaa: Log MSAA resources
anisohq: Use high quality anisotropic filtering
notiling: Disable tiling
noimmd: Disable immediate mode
noopt: Disable shader optimizations
nocbzb: Disable fast color clear
nozmask: Disable zbuffer compression
nohiz: Disable hierarchical zbuffer
nocmask: Disable AA compression and fast AA clear
notcl: Disable hardware accelerated Transform/Clip/Lighting
ieeemath: Force IEEE versions of VS math opcodes where applicable and also IEEE handling of multiply by zero (R5xx only)
ffmath: Force FF versions of VS math opcodes where applicable and 0 * anything = 0 rules in FS

Asahi driver environment variables¶

ASAHI_MESA_DEBUG¶

a comma-separated list of named flags, which do various things:

trace: Trace work submitted to the GPU to files, using the agxdecode infrastructure. This produces a large volume of data, so should be used with caution. The traces are written to agxdecode.dump, but this can be overridden using AGXDECODE_DUMP_FILE.
no16: Disable 16-bit floating point support. This may workaround application bugs in certain OpenGL ES applications originally written for desktops. If such applications are found in the wild, they should be fixed upstream (if possible) or added in the Mesa-wide driconf (if closed source).
dirty: In debug builds only: disable dirty tracking optimizations.
nowc: Disable write-combining (force all allocations to be write-through). This may be useful for diagnosing certain performance issues. Note imported buffers may still be write-combined.

AGX_MESA_DEBUG¶

a comma-separated list of named flags, which do various things:

shaders: Print shaders being compiled at various stages in the pipeline.
shaderdb: Print statistics about compiled shaders.
verbose: Disassemble in verbose mode, including additional information that may be useful for debugging.
internal: Include even internal shaders (as produced for clears, blits, and such) when printing shaders. Without this flag, internal shaders are ignored by the shaders and shaderdb flags.
novalidate: In debug builds only: skip internal intermediate representation validation.
noopt: Disable various backend optimizations.

PowerVR driver environment variables¶

PVR_DEBUG¶: A comma-separated list of debug options. Use PVR_DEBUG=help to print a list of available options.

ROGUE_DEBUG¶

a comma-separated list of named flags for the Rogue compiler, which do various things:

nir: Print the input NIR to stdout.
nir_passes: Print the output of each NIR pass to stdout.
ir: Print the input Rogue IR to stdout.
ir_passes: Print the output of each Rogue IR pass to stdout.
ir_details: Includes additional details when printing Rogue IR.
vld_skip: Skips the compiler validation step.
vld_nonfatal: Prints all the validation errors instead of stopping after the first.

ROGUE_COLOR¶: if set to auto Rogue IR will be colorized if stdout is not a pipe. Color is forced off if set to off/0 or on if set to on/1. Defaults to auto.

i915 driver environment variables¶

I915_DEBUG¶: Debug flags for the i915 driver.

I915_NO_HW¶: Stop the i915 driver from submitting commands to the hardware.

I915_DUMP_CMD¶: Dump all commands going to the hardware.

Freedreno driver environment variables¶

FD_MESA_DEBUG¶: Debug flags for the Freedreno driver.

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

Vulkan loader environment variables¶

These variable are handled by Khronos’ Vulkan loader, not by Mesa, but they are documented here as we reference them in other places in our docs.

VK_DRIVER_FILES¶

Force the loader to use the specific driver JSON files. The value contains a list of delimited full path listings to driver JSON Manifest files and/or paths to folders containing driver JSON files.

See Vulkan loader docs on environment variables.

VK_LOADER_LAYERS_ENABLE¶: A comma-delimited list of globs to search for in known layers and used to select only the layers whose layer name matches one or more of the provided globs. Known layers are those which are found by the loader taking into account default search paths and other environment variables (like VK_LAYER_PATH).

See Vulkan loader docs on environment variables.

VK_ICD_FILENAMES¶: Deprecated, replaced by VK_DRIVER_FILES.

VK_INSTANCE_LAYERS¶: Deprecated, replaced by VK_LOADER_LAYERS_ENABLE.