Commit Graph

121825 Commits

Author SHA1 Message Date
Rob Clark 150a914a78 freedreno: Convert one last mtx_t -> simple_mtx_t
Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7717>
2020-11-23 16:04:52 +00:00
Rob Clark 8651cfbbf0 freedreno: emit_marker() cleanup
1) Propagate the change to only emit markers in debug builds (and add
   the WFI that ensures they are synchronized with GPU.  We could
   consider dropping them entirely, since the GPU devcoredump support
   in newer kernels is more useful.  But it is still an occasionally
   useful fallback.

2) Use p_atomic_inc_return() to placate helgrind

Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7717>
2020-11-23 16:04:52 +00:00
Lionel Landwerlin b039e03f55 mesa: add an environment variable to default enable INTEL_blackhole
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7640>
2020-11-23 11:56:48 +00:00
Lionel Landwerlin f5610d9949 st: trigger noop if the default value is not true
v2: Verify that PIPE_CAP_FRONTEND_NOOP is available before calling vfunc (Icecream95)

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com> (v1)
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7640>
2020-11-23 11:56:48 +00:00
Connor Abbott 76ade57fa6 ir3/ra: Fix array reg liveness in scalar pass
Assigning an array reg removes IR3_REG_ARRAY, which means that
definitions and uses can't be tracked back to the array register's name
and liveness for the components of the array aren't correctly
calculated. To fix this we delay assigning array registers until the
scalar pass.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7711>
2020-11-23 11:33:13 +00:00
Samuel Pitoiset 88b5a2b80b nir: fix gathering cross invocation info
Fixes: 5b77b14448 ("nir: Use src_is_invocation_id in get_deref_info.")
Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7730>
2020-11-23 11:00:17 +00:00
jzielins 79bd8edd87 swr: Pass draw start information to state update mechanism
This fixes crash in many workloads/tests

Reviewed-by: Krzysztof Raszkowski <krzysztof.raszkowski@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7728>
2020-11-23 10:15:28 +00:00
Alejandro Piñeiro ce5c23eb00 v3dv/cmd_buffer: missing (uint8_t *) casting when calling memcmp
Caused to return early wrongly on CmdPushConstants with some tests
using several calls to that method. As we are here we are also
replacing the (void *) casting at the memcpy below.

Fixes: e1c8041cde ("v3dv: try harder to skip emission of redundant state")

Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7718>
2020-11-23 09:51:24 +01:00
Samuel Pitoiset 14ec91b131 radv: dump BO ranges into bo_ranges.log instead of stderr
Like other dumps during GPU hang detection.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7706>
2020-11-23 08:44:54 +01:00
Samuel Pitoiset 4ffa6acb0d radv: add RADV_DEBUG=noumr to disable UMR logs during GPU hang detection
Sometimes UMR logs can't be dumped and you would get permission
denied, even if the UMR binary has the setuid bit enabled.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7706>
2020-11-23 08:44:52 +01:00
Samuel Pitoiset a61a398f7e radv: dump application info in the GPU hang report
Like the name, version, as well as the engine and the API version.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7706>
2020-11-23 08:44:52 +01:00
Samuel Pitoiset 8d7f78ccf8 radv: append a time string to the hang report dump directory
Using the PID only isn't really informative.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7706>
2020-11-23 08:44:52 +01:00
Samuel Pitoiset 15e1b530f6 radv: print more debug messages when generating a hang report
If for some reasons the driver can't generate the hang report properly.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7706>
2020-11-23 08:44:52 +01:00
Marek Olšák f7364c9fe0 radeonsi: don't allocate LDS for TCS inputs if it's not used
Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7623>
2020-11-23 02:22:21 +00:00
Marek Olšák a4ba51e5be radeonsi: don't insert barrier between VS/TCS if all TCS inputs come from VGPRs
Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7623>
2020-11-23 02:22:21 +00:00
Marek Olšák 61fe66a2e4 radeonsi: pass VS->TCS IO via VGPRs if VS and TCS have the same thread count
It can only be done if a TCS input is accessed without indirect indexing and
with gl_InvocationID as the vertex index, and the number of VS and TCS threads
is the same.

This eliminates LDS stores and loads for VS->TCS IO, reducing shader lifetime
and LDS traffic.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7623>
2020-11-23 02:22:21 +00:00
Marek Olšák 6f13034265 ac/llvm: prepare for passing VS->TCS IO via VGPRs
- bump AC_MAX_ARGS
- add vertex_index_is_invoc_id parameter into load_tess_varyings

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7623>
2020-11-23 02:22:21 +00:00
Marek Olšák 98b2aacfbf radeonsi: remove unnecessary NULL checking in NIR tess functions
param_index is always checked for non-NULL later.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7623>
2020-11-23 02:22:21 +00:00
Marek Olšák 1190808eca radeonsi: if VS and TCS have the same number of threads, merge the conditonals
Instead of:
    if (VS) {
	VS;
    }
    if (TCS) {
	TCS;
    }

Do this if the number of threads is the same in VS and TCS:
    exec = enabled_threads;
    VS;
    TCS;

Skipping declare_vb_descriptor_input_sgprs is needed to match the VS return
values.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7623>
2020-11-23 02:22:21 +00:00
Marek Olšák 0aba174361 radeonsi: always return void from si_build_wrapper_function
It's the end of the shader, there are no return values.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7623>
2020-11-23 02:22:21 +00:00
Marek Olšák a56e92c79e radeonsi: merge TCS and TCS epilog conditional blocks
Instead of:
    if (TCS) {
       TCS;
    }
    if (TCS && epilog) {
       epilog;
    }

Do:
    if (TCS) {
	TCS;
	if (epilog) {
	    epilog;
    }

Only monolithic shaders can do it.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7623>
2020-11-23 02:22:21 +00:00
Marek Olšák c605de30eb radeonsi: don't generate a dead conditional in si_write_tess_factors on gfx9+
Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7623>
2020-11-23 02:22:21 +00:00
Marek Olšák 5df5ee2722 radeonsi: limit HS LDS usage per workgroup to 16K to allow at least 2 WGs/CU
This increases occupancy when the LDS size is e.g. 20K for 3 waves.
If we limit the size to 16K, we can fit 2 workgroups with 2 waves each,
so 4 waves in total.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7623>
2020-11-23 02:22:21 +00:00
Marek Olšák bdee9dc633 radeonsi: don't allocate LDS for TCS outputs if they are not read
This reduces LDS usage by 50% in Unigine Heaven.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7623>
2020-11-23 02:22:21 +00:00
Marek Olšák 10beddf659 radeonsi: don't leave more than 8 unoccupied lanes in HS
Previously it was 16 and bigger patches would always trim the patch count
needlessly.

There are 2 variables to consider:
- lane occupancy
- LDS usage (limiting wave occupancy)

If LDS size is 32 KB (max limit per CU) for 3 waves and we can't maximize
occupancy, it's better to leave some lanes unoccupied because using 2
waves would decrease the LDS size to 21 KB, which is not enough to fit
another workgroup on the CU.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7623>
2020-11-23 02:22:21 +00:00
Marek Olšák 9b5b5cbc53 radeonsi: adjust tess SGPRs to allow fully occupied 3 HS waves of triangles
With triangles and 3 HS waves, 3 lanes were unoccupied. Adjust the SGPR
encoding to allow 1 more triangle to fit there.

Some of the fields are not large enough, but they weren't large enough
before either.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7623>
2020-11-23 02:22:20 +00:00
Marek Olšák 9659384744 ac/nir: fix a typo in ac_are_tessfactors_def_in_all_invocs
I think it only made the pass return false if there was a barrier

Fixes: 2832bc972b - ac/nir_to_llvm: add ac_are_tessfactors_def_in_all_invocs()

Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7623>
2020-11-23 02:22:20 +00:00
Gert Wollny bb6bdeb230 r600/sfn: Correctly lower all int64
Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7724>
2020-11-22 22:55:31 +00:00
Vinson Lee 861d48ea0b nv50/ir: Initialize Program members in constructor.
Fix defects reported by Coverity Scan.

uninit_member: Non-static class member tlsSize is not initialized in this constructor nor in any functions that it calls.
uninit_member: Non-static class member driver is not initialized in this constructor nor in any functions that it calls.
uninit_member: Non-static class member driver_out is not initialized in this constructor nor in any functions that it calls.

Signed-off-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7703>
2020-11-22 14:24:35 -08:00
Gert Wollny 8976918efa r600/sfn: use a per stream index register in GS
Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7714>
2020-11-22 15:38:08 +00:00
Gert Wollny 335c48ab33 r600/sfn: lower bool to int32 only after common optimizations
Fixes: f79b7fcf7c
   r600/sfn: use 32 bit bools

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7714>
2020-11-22 15:38:08 +00:00
Timur Kristóf 5b77b14448 nir: Use src_is_invocation_id in get_deref_info.
Signed-off-by: Timur Kristof <timur.kristof@gmail.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7622>
2020-11-21 19:38:57 -05:00
Marek Olšák e78c089aae nir: fix gathering patch IO usage with lowered IO
Fixes: 17af07024d - nir: gather all IO info from IO intrinsics

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7622>
2020-11-21 19:38:55 -05:00
Marek Olšák aadfdb962f nir: fix gathering TCS cross invocation access with lowered IO
Fixes: abe9588ff0 - nir: gather tess.tcs_cross_invocation info from lowered IO intrinsics

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7622>
2020-11-21 19:38:53 -05:00
Marek Olšák 9edfbd6296 mesa: lock Shared->TexMutex only once for a glthread batch
This removes a lot of locking from the driver thread.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7053>
2020-11-21 21:02:56 +00:00
Marek Olšák 8e7270de55 mesa: lock Shared->BufferObjects only once for a glthread batch
This removes a lot of locking from the driver thread.

If multiple contexts sharing buffers submit GL calls from multiple threads,
they will be serialized by this mutex. I can add a driconf option to turn
off this optimization if needed, but I currently don't anticipate to see
GL apps that use multiple shared contexts in different threads
simultaneously.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7053>
2020-11-21 21:02:56 +00:00
Marek Olšák b8684672ff glthread: make glGetActiveUniform return without syncing
We just need to track glLinkProgram and glDeleteProgram.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7053>
2020-11-21 21:02:56 +00:00
Marek Olšák 5f820b38d4 mesa: make error handling for glGetActiveUniform glthread-safe
glGetActiveUniform will be called from the app thread directly.
This is safe if a few conditions are met.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7053>
2020-11-21 21:02:56 +00:00
Marek Olšák ac4dc6e139 mesa: add glInternalSetError for glthread
glthread wants to set GL errors, but has to do it by adding the SetError
call into the queue for it to be thread-safe.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7053>
2020-11-21 21:02:56 +00:00
Bas Nieuwenhuizen 347a3d68cd radv: Dump BO VA ranges on hang.
To make it easier to figure out if a given VA is valid or not.

Gitlab: https://gitlab.freedesktop.org/mesa/mesa/-/issues/3620
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7205>
2020-11-21 14:25:53 +00:00
Vinson Lee ba9906fc8f clover: Initialize command_queue member _props.
Fix defect reported by Coverity Scan.

Uninitialized scalar variable (UNINIT)
uninit_use: Using uninitialized value this->_props.
    _props |= properties[i + 1];

Fixes: e42a7fa037 ("clover: add support command queue properties")
Signed-off-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7701>
2020-11-20 17:55:27 -08:00
Rhys Perry 14186a1b84 aco/tests: add Builder::v_mul_imm() tests
Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5390>
2020-11-20 19:50:32 +00:00
Rhys Perry aab507c6b0 aco: use v_mul_imm() for some nir_op_imul
Some of the optimizations v_mul_imm() does are complex and very
target-specific and not suitable to do in ACO's optimizer.

fossil-db (Vega):
Totals from 49135 (35.76% of 137413) affected shaders:
SGPRs: 2698547 -> 2696103 (-0.09%); split: -0.16%, +0.07%
VGPRs: 2301412 -> 2301600 (+0.01%); split: -0.01%, +0.02%
SpillSGPRs: 51520 -> 51519 (-0.00%)
CodeSize: 168798572 -> 169164012 (+0.22%); split: -0.00%, +0.22%
MaxWaves: 306553 -> 306539 (-0.00%); split: +0.00%, -0.01%
Instrs: 33423982 -> 33506598 (+0.25%); split: -0.00%, +0.25%
Cycles: 1807800632 -> 1804101376 (-0.20%); split: -0.20%, +0.00%

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5390>
2020-11-20 19:50:32 +00:00
Rhys Perry 02c5519e6c aco: try harder to not create v_mul_lo_u32
fossil-db (Vega):
Totals from 4 (0.00% of 137413) affected shaders:
CodeSize: 13708 -> 13716 (+0.06%)
Instrs: 2742 -> 2744 (+0.07%)
Cycles: 24348 -> 24236 (-0.46%)

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5390>
2020-11-20 19:50:31 +00:00
Rhys Perry 8ca23bcf39 aco: copy constant to sgpr in Builder::v_mul_imm()
No fossil-db changes.

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5390>
2020-11-20 19:50:31 +00:00
Rhys Perry 756bb29391 aco: create vgpr constant copies using v_bfrev_b32
Looks like this worked once but broke at some point.

fossil-db (Vega):
Totals from 577 (0.42% of 137413) affected shaders:
CodeSize: 3822052 -> 3818720 (-0.09%)

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5390>
2020-11-20 19:50:31 +00:00
Rhys Perry 4d93fc25f0 aco: count v_mul_lo_u32 as 16 cycles
There are more, but this is a common one.

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5390>
2020-11-20 19:50:31 +00:00
Rhys Perry 70d665d981 aco: don't create v_mov_b32 in v_mul_imm()
We switched to p_parallelcopy for everything else.

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5390>
2020-11-20 19:50:31 +00:00
Krunal Patel 35613c752f radeon/vce: Bitrate not updated when changing framerate
Issue: Encoding parameters not updated after changing FrameRate

Root Cause:
In rvce_begin_frame, need_rate_control was enabled if the target_bitrate,
quant_i_frames, quant_p_frames, quant_b_frames or rate_ctrl_method
changes. Due to this the rate_control() was not updating the encoder
parameters with new framerate, peak_bits_per_picture_integer and
avg_target_bits_per_picture

Fix:
Added the condition where we will check if there is a change in
other parameters and enable need_rate_control. Eventually updating the
encoder parameters with new framerate and bitrate.

Signed-off-by: Krunal Patel <krunalkumarmukeshkumar.patel@amd.corp-partner.google.com>
Reviewed-by: Leo Liu <leo.liu@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7696>
2020-11-20 23:35:01 +05:30
Adam Jackson a59b1b18a9 glx, egl: Add LIBGL_DRI2_DISABLE environment variable
For orthogonality with LIBGL_DRI3_DISABLE.

Reviewed-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7688>
2020-11-20 16:15:57 +00:00