From e5311ba1acba738346a18ef661b0f8bbc33bba8e Mon Sep 17 00:00:00 2001 From: Francisco Jerez Date: Thu, 15 Sep 2016 21:43:18 -0700 Subject: [PATCH] i965/ir: Test thread dispatch packing assumptions. Not [originally] intended for upstream. Should cause a GPU hang if some thread is executed with a non-contiguous dispatch mask breaking assumptions of brw_stage_has_packed_dispatch(). Doesn't cause any CTS, DEQP or Piglit regressions, while replacing brw_stage_has_packed_dispatch() with a dummy implementation that unconditionally returns true on top of this patch causes multiple GPU hangs. v2: Refactor into a separate function instead of emitting the test code directly from emit_nir_code(), drop VEC4 test and clean up slightly for upstream. (Jason) Reviewed-by: Jason Ekstrand --- src/mesa/drivers/dri/i965/brw_fs.cpp | 30 ++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp index b60ec71888a..1483f41de97 100644 --- a/src/mesa/drivers/dri/i965/brw_fs.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp @@ -6786,3 +6786,33 @@ brw_compile_cs(const struct brw_compiler *compiler, void *log_data, return g.get_assembly(final_assembly_size); } + +/** + * Test the dispatch mask packing assumptions of + * brw_stage_has_packed_dispatch(). Call this from e.g. the top of + * fs_visitor::emit_nir_code() to cause a GPU hang if any shader invocation is + * executed with an unexpected dispatch mask. + */ +static UNUSED void +brw_fs_test_dispatch_packing(const fs_builder &bld) +{ + const gl_shader_stage stage = bld.shader->stage; + + if (brw_stage_has_packed_dispatch(bld.shader->devinfo, stage, + bld.shader->stage_prog_data)) { + const fs_builder ubld = bld.exec_all().group(1, 0); + const fs_reg tmp = component(bld.vgrf(BRW_REGISTER_TYPE_UD), 0); + const fs_reg mask = (stage == MESA_SHADER_FRAGMENT ? brw_vmask_reg() : + brw_dmask_reg()); + + ubld.ADD(tmp, mask, brw_imm_ud(1)); + ubld.AND(tmp, mask, tmp); + + /* This will loop forever if the dispatch mask doesn't have the expected + * form '2^n-1', in which case tmp will be non-zero. + */ + bld.emit(BRW_OPCODE_DO); + bld.CMP(bld.null_reg_ud(), tmp, brw_imm_ud(0), BRW_CONDITIONAL_NZ); + set_predicate(BRW_PREDICATE_NORMAL, bld.emit(BRW_OPCODE_WHILE)); + } +} -- 2.30.2