# 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 set then the cache will be stored in `$MESA_SHADER_CACHE_DIR/mesa_shader_cache_db`. If this variable is not set, then the cache will be stored in `$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 set, the cache will be stored in `$MESA_SHADER_CACHE_DIR/mesa_shader_cache_sf`, or else within `$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 set, the cache will be stored in `$MESA_SHADER_CACHE_DIR/mesa_shader_cache`, or else within `$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_PER_SUBMIT

  Enables per-submit capture for compute-only workload. Disabled by default and only valid with MESA_VK_TRACE=rgp.

MESA_VK_TRACE_FRAME

  Specifies a frame index at which a trace capture is automatically triggered. Ignored when MESA_VK_TRACE_PER_SUBMIT is enabled.

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`) Ignored when MESA_VK_TRACE_PER_SUBMIT is enabled.

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.

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.

## 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

  `rt_notrace`

    skip trace rays operation (does not disable AS generation; see bvh_no_build)

  `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 `brw_asm` or `elk_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 `brw_asm` or `elk_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_DEBUG

  Accepts the following comma-separated list of flags:

  `bindless`

    Forces all descriptor sets to use the internal Binding Model

  `no-gpl`

    Disables VK_KHR_graphics_pipeline_library support

  `no-secondary-call`

    Disables secondary command buffer calls

  `no-sparse`

    Disables sparse support

  `sparse-trtt`

    Forces use of TR-TT hardware for sparse support

  `video-decode`

    Enables video decoding support

  `video-encode`

    Enables video encoding support

  `shader-hash`

    > Emits dummy (MI_STORE_DATA_IMM) instructions containing the shader source hash, preceding shader programming instructions (internal shaders & ray-tracing shaders are omitted)

    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_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_PRINTF_BUFFER_SIZE

  Specifies the size of the printf buffer.

ANV_QUEUE_OVERRIDE

  Override exposed queue families & counts. The variable is a comma separated list of queue overrides. To override the number queues:

  - `gc` is for graphics queues with compute support

  - `g` is for graphics queues with no compute support

  - `c` is for compute queues with no graphics support

  - `v` is for video queues with no graphics support

  - `b` is for copy (blitter) queues with no graphics support

  For example, `ANV_QUEUE_OVERRIDE=gc=2,c=1` would override the number of advertised queues to be 2 queues with graphics+compute support, and 1 queue with compute-only support.

  `ANV_QUEUE_OVERRIDE=c=1` would override the number of advertised queues to include 1 queue with compute-only support, but it will not change the number of graphics+compute queues.

  `ANV_QUEUE_OVERRIDE=gc=0,c=1` would override the number of advertised queues to include 1 queue with compute-only support, and it would override the number of graphics+compute queues to be 0.

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.

## Hasvk driver environment variables

HASVK_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.

HASVK_ALWAYS_BINDLESS

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

HASVK_QUEUE_OVERRIDE

  Override exposed queue families & counts. The variable is a comma separated list of queue overrides. To override the number queues:

  - `gc` is for graphics queues with compute support

  - `g` is for graphics queues with no compute support

  - `c` is for compute queues with no graphics support

  - `v` is for video queues with no graphics support

  - `b` is for copy (blitter) queues with no graphics support

  For example, `HASVK_QUEUE_OVERRIDE=gc=2,c=1` would override the number of advertised queues to be 2 queues with graphics+compute support, and 1 queue with compute-only support.

  `HASVK_QUEUE_OVERRIDE=c=1` would override the number of advertised queues to include 1 queue with compute-only support, but it will not change the number of graphics+compute queues.

  `HASVK_QUEUE_OVERRIDE=gc=0,c=1` would override the number of advertised queues to include 1 queue with compute-only support, and it would override the number of graphics+compute queues to be 0.

HASVK_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).

## 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`.

## 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.

## 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 for GFX10 and GFX10.3

  `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

  `pso_history`

    dump PSO history (pipeline hash + shader VA) to /tmp/radv_pso_history.log. Useful for debugging GPU hangs with UMR and Fossilize.

  `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 for GFX11+

  `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 on GFX6-9

  `video_encode`

    enable experimental video encoding support on GFX6-9

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`.

PCO_DEBUG

  A comma-separated list of named flags for the PCO compiler, which control various compilation options:

  `val_skip`

    Skip IR validation.

  `reindex`

    Reindex IR at the end of each pass.

PCO_SKIP_PASSES

  A comma-separated list of passes to skip.

PCO_PRINT

  A comma-separated list of named flags for the PCO compiler, which control debug printing options:

  `vs`

    Print the IR for vertex shaders.

  `fs`

    Print the IR for fragment shaders.

  `cs`

    Print the IR for compute shaders.

  `all`

    Print the IR for all shaders.

  `internal`

    Print the IR for internal shader types.

  `passes`

    Print the IR after each pass.

  `nir`

    Print the resulting NIR.

  `binary`

    Print the resulting binary.

  `verbose`

    Print verbose IR.

  `ra`

    Print register alloc info.

PCO_COLOR

  if set to `auto` PCO 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`.