diff --git a/src/intel/compiler/brw_fs.cpp b/src/intel/compiler/brw_fs.cpp index 52a54fecdaa..b19f8fab3a9 100644 --- a/src/intel/compiler/brw_fs.cpp +++ b/src/intel/compiler/brw_fs.cpp @@ -8274,6 +8274,16 @@ brw_compile_fs(const struct brw_compiler *compiler, void *log_data, prog_data->reg_blocks_8 = brw_register_blocks(v8.grf_used); } + /* Limit dispatch width to simd8 with dual source blending on gen8. + * See: https://gitlab.freedesktop.org/mesa/mesa/issues/1917 + */ + if (devinfo->gen == 8 && prog_data->dual_src_blend && + !(INTEL_DEBUG & DEBUG_NO8)) { + assert(!use_rep_send); + v8.limit_dispatch_width(8, "gen8 workaround: " + "using SIMD8 when dual src blending.\n"); + } + if (v8.max_dispatch_width >= 16 && likely(!(INTEL_DEBUG & DEBUG_NO16) || use_rep_send)) { /* Try a SIMD16 compile */