From 19ab08200179e71af42ce6e1b91f502e50f915b3 Mon Sep 17 00:00:00 2001 From: Plamena Manolova Date: Tue, 12 Mar 2019 21:25:36 +0200 Subject: [PATCH] i965: Disable ARB_fragment_shader_interlock for platforms prior to GEN9 ARB_fragment_shader_interlock depends on memory fences to ensure fragment ordering and this ordering guarantee is only supported from GEN9 onwards. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109980 Fixes: 939312702e35 "i965: Add ARB_fragment_shader_interlock support." Signed-off-by: Plamena Manolova Reviewed-by: Jason Ekstrand --- src/intel/compiler/brw_fs_generator.cpp | 1 + src/mesa/drivers/dri/i965/intel_extensions.c | 25 +++++++++++++++++++- 2 files changed, 25 insertions(+), 1 deletion(-) diff --git a/src/intel/compiler/brw_fs_generator.cpp b/src/intel/compiler/brw_fs_generator.cpp index 649dd999a0e..c24d4eb7cab 100644 --- a/src/intel/compiler/brw_fs_generator.cpp +++ b/src/intel/compiler/brw_fs_generator.cpp @@ -2100,6 +2100,7 @@ fs_generator::generate_code(const cfg_t *cfg, int dispatch_width) break; case SHADER_OPCODE_INTERLOCK: + assert(devinfo->gen >= 9); /* The interlock is basically a memory fence issued via sendc */ brw_memory_fence(p, dst, BRW_OPCODE_SENDC); break; diff --git a/src/mesa/drivers/dri/i965/intel_extensions.c b/src/mesa/drivers/dri/i965/intel_extensions.c index d7080fb21b4..afca881e5d9 100644 --- a/src/mesa/drivers/dri/i965/intel_extensions.c +++ b/src/mesa/drivers/dri/i965/intel_extensions.c @@ -254,7 +254,6 @@ intelInitExtensions(struct gl_context *ctx) ctx->Extensions.EXT_shader_samples_identical = true; ctx->Extensions.OES_primitive_bounding_box = true; ctx->Extensions.OES_texture_buffer = true; - ctx->Extensions.ARB_fragment_shader_interlock = true; if (can_do_pipelined_register_writes(brw->screen)) { ctx->Extensions.ARB_draw_indirect = true; @@ -327,6 +326,30 @@ intelInitExtensions(struct gl_context *ctx) ctx->Extensions.KHR_blend_equation_advanced_coherent = true; ctx->Extensions.KHR_texture_compression_astc_ldr = true; ctx->Extensions.KHR_texture_compression_astc_sliced_3d = true; + + /* + * From the Skylake PRM Vol. 7 (Memory Fence Message, page 221): + * "A memory fence message issued by a thread causes further messages + * issued by the thread to be blocked until all previous data port + * messages have completed, or the results can be globally observed from + * the point of view of other threads in the system." + * + * From the Haswell PRM Vol. 7 (Memory Fence, page 256): + * "A memory fence message issued by a thread causes further messages + * issued by the thread to be blocked until all previous messages issued + * by the thread to that data port (data cache or render cache) have + * been globally observed from the point of view of other threads in the + * system." + * + * Summarized: For ARB_fragment_shader_interlock to work, we need to + * ensure memory access ordering for all messages to the dataport from + * all threads. Memory fence messages prior to SKL only provide memory + * access ordering for messages from the same thread, so we can only + * support the feature from Gen9 onwards. + * + */ + + ctx->Extensions.ARB_fragment_shader_interlock = true; } if (gen_device_info_is_9lp(devinfo)) -- 2.30.2