[Mesa-dev] [PATCH 5/5] radeonsi: implement the workaround for Rocket League - postponed TGSI kill

Marek Olšák maraeo at gmail.com
Tue Jun 20 22:54:41 UTC 2017


From: Marek Olšák <marek.olsak at amd.com>

Do KILL at the end of shaders so as not to break WQM.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100070
---
 src/gallium/drivers/radeon/r600_pipe_common.c     |  5 +++++
 src/gallium/drivers/radeon/r600_pipe_common.h     |  1 +
 src/gallium/drivers/radeonsi/si_shader.c          |  9 +++++++++
 src/gallium/drivers/radeonsi/si_shader_internal.h |  1 +
 src/gallium/drivers/radeonsi/si_shader_tgsi_alu.c | 21 +++++++++++++++++++++
 5 files changed, 37 insertions(+)

diff --git a/src/gallium/drivers/radeon/r600_pipe_common.c b/src/gallium/drivers/radeon/r600_pipe_common.c
index 04f7fc1..fd67d9a 100644
--- a/src/gallium/drivers/radeon/r600_pipe_common.c
+++ b/src/gallium/drivers/radeon/r600_pipe_common.c
@@ -1375,20 +1375,25 @@ bool r600_common_screen_init(struct r600_common_screen *rscreen,
 
 	r600_init_screen_texture_functions(rscreen);
 	r600_init_screen_query_functions(rscreen);
 
 	rscreen->family = rscreen->info.family;
 	rscreen->chip_class = rscreen->info.chip_class;
 	rscreen->debug_flags = debug_get_flags_option("R600_DEBUG", common_debug_options, 0);
 	rscreen->has_rbplus = false;
 	rscreen->rbplus_allowed = false;
 
+	/* Set the flag in debug_flags, so that the shader cache takes it
+	 * into account. */
+	if (flags & PIPE_SCREEN_ENABLE_CORRECT_TGSI_DERIVATIVES_AFTER_KILL)
+		rscreen->debug_flags |= DBG_FS_CORRECT_DERIVS_AFTER_KILL;
+
 	r600_disk_cache_create(rscreen);
 
 	slab_create_parent(&rscreen->pool_transfers, sizeof(struct r600_transfer), 64);
 
 	rscreen->force_aniso = MIN2(16, debug_get_num_option("R600_TEX_ANISO", -1));
 	if (rscreen->force_aniso >= 0) {
 		printf("radeon: Forcing anisotropy filter to %ix\n",
 		       /* round down to a power of two */
 		       1 << util_logbase2(rscreen->force_aniso));
 	}
diff --git a/src/gallium/drivers/radeon/r600_pipe_common.h b/src/gallium/drivers/radeon/r600_pipe_common.h
index e67982a..b22a3a7 100644
--- a/src/gallium/drivers/radeon/r600_pipe_common.h
+++ b/src/gallium/drivers/radeon/r600_pipe_common.h
@@ -78,20 +78,21 @@
 #define DBG_PS			(1 << 8)
 #define DBG_CS			(1 << 9)
 #define DBG_TCS			(1 << 10)
 #define DBG_TES			(1 << 11)
 #define DBG_NO_IR		(1 << 12)
 #define DBG_NO_TGSI		(1 << 13)
 #define DBG_NO_ASM		(1 << 14)
 #define DBG_PREOPT_IR		(1 << 15)
 #define DBG_CHECK_IR		(1 << 16)
 #define DBG_NO_OPT_VARIANT	(1 << 17)
+#define DBG_FS_CORRECT_DERIVS_AFTER_KILL (1 << 18)
 /* gaps */
 #define DBG_TEST_DMA		(1 << 20)
 /* Bits 21-31 are reserved for the r600g driver. */
 /* features */
 #define DBG_NO_ASYNC_DMA	(1llu << 32)
 #define DBG_NO_HYPERZ		(1llu << 33)
 #define DBG_NO_DISCARD_RANGE	(1llu << 34)
 #define DBG_NO_2D_TILING	(1llu << 35)
 #define DBG_NO_TILING		(1llu << 36)
 #define DBG_SWITCH_ON_EOP	(1llu << 37)
diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index c9fe250..108386e 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -3242,20 +3242,23 @@ static void si_llvm_return_fs_outputs(struct lp_build_tgsi_context *bld_base)
 	struct si_shader_context *ctx = si_shader_context(bld_base);
 	struct si_shader *shader = ctx->shader;
 	struct tgsi_shader_info *info = &shader->selector->info;
 	LLVMBuilderRef builder = ctx->gallivm.builder;
 	unsigned i, j, first_vgpr, vgpr;
 
 	LLVMValueRef color[8][4] = {};
 	LLVMValueRef depth = NULL, stencil = NULL, samplemask = NULL;
 	LLVMValueRef ret;
 
+	if (ctx->postponed_kill)
+		ac_build_kill(&ctx->ac, LLVMBuildLoad(builder, ctx->postponed_kill, ""));
+
 	/* Read the output values. */
 	for (i = 0; i < info->num_outputs; i++) {
 		unsigned semantic_name = info->output_semantic_name[i];
 		unsigned semantic_index = info->output_semantic_index[i];
 
 		switch (semantic_name) {
 		case TGSI_SEMANTIC_COLOR:
 			assert(semantic_index < 8);
 			for (j = 0; j < 4; j++) {
 				LLVMValueRef ptr = ctx->outputs[i][j];
@@ -5511,20 +5514,26 @@ static bool si_compile_tgsi_main(struct si_shader_context *ctx,
 
 	if (ctx->type == PIPE_SHADER_GEOMETRY) {
 		int i;
 		for (i = 0; i < 4; i++) {
 			ctx->gs_next_vertex[i] =
 				lp_build_alloca(&ctx->gallivm,
 						ctx->i32, "");
 		}
 	}
 
+	if (ctx->type == PIPE_SHADER_FRAGMENT && sel->info.uses_kill &&
+	    ctx->screen->b.debug_flags & DBG_FS_CORRECT_DERIVS_AFTER_KILL) {
+		/* This is initialized to 0.0 = not kill. */
+		ctx->postponed_kill = lp_build_alloca(&ctx->gallivm, ctx->f32, "");
+	}
+
 	if (!lp_build_tgsi_llvm(bld_base, sel->tokens)) {
 		fprintf(stderr, "Failed to translate shader from TGSI to LLVM\n");
 		return false;
 	}
 
 	si_llvm_build_ret(ctx, ctx->return_value);
 	return true;
 }
 
 /**
diff --git a/src/gallium/drivers/radeonsi/si_shader_internal.h b/src/gallium/drivers/radeonsi/si_shader_internal.h
index 5ccde71..3556e69 100644
--- a/src/gallium/drivers/radeonsi/si_shader_internal.h
+++ b/src/gallium/drivers/radeonsi/si_shader_internal.h
@@ -210,20 +210,21 @@ struct si_shader_context {
 	unsigned range_md_kind;
 	unsigned fpmath_md_kind;
 	LLVMValueRef fpmath_md_2p5_ulp;
 
 	/* Preloaded descriptors. */
 	LLVMValueRef esgs_ring;
 	LLVMValueRef gsvs_ring[4];
 
 	LLVMValueRef lds;
 	LLVMValueRef gs_next_vertex[4];
+	LLVMValueRef postponed_kill;
 	LLVMValueRef return_value;
 
 	LLVMTypeRef voidt;
 	LLVMTypeRef i1;
 	LLVMTypeRef i8;
 	LLVMTypeRef i32;
 	LLVMTypeRef i64;
 	LLVMTypeRef i128;
 	LLVMTypeRef f32;
 	LLVMTypeRef v2i32;
diff --git a/src/gallium/drivers/radeonsi/si_shader_tgsi_alu.c b/src/gallium/drivers/radeonsi/si_shader_tgsi_alu.c
index 9fa56c7..12f8de4 100644
--- a/src/gallium/drivers/radeonsi/si_shader_tgsi_alu.c
+++ b/src/gallium/drivers/radeonsi/si_shader_tgsi_alu.c
@@ -53,20 +53,41 @@ static void kill_if_fetch_args(struct lp_build_tgsi_context *bld_base,
 	emit_data->args[0] = LLVMBuildSelect(builder, conds[0],
 					lp_build_const_float(gallivm, -1.0f),
 					bld_base->base.zero, "");
 }
 
 static void kil_emit(const struct lp_build_tgsi_action *action,
 		     struct lp_build_tgsi_context *bld_base,
 		     struct lp_build_emit_data *emit_data)
 {
 	struct si_shader_context *ctx = si_shader_context(bld_base);
+	LLVMBuilderRef builder = ctx->gallivm.builder;
+
+	if (ctx->postponed_kill) {
+		if (emit_data->inst->Instruction.Opcode == TGSI_OPCODE_KILL_IF) {
+			LLVMValueRef val;
+
+			/* Take the minimum kill value. This is the same as OR
+			 * between 2 kill values. If the value is negative,
+			 * the pixel will be killed.
+			 */
+			val = LLVMBuildLoad(builder, ctx->postponed_kill, "");
+			val = lp_build_emit_llvm_binary(bld_base, TGSI_OPCODE_MIN,
+							val, emit_data->args[0]);
+			LLVMBuildStore(builder, val, ctx->postponed_kill);
+		} else {
+			LLVMBuildStore(builder,
+				       LLVMConstReal(ctx->f32, -1),
+				       ctx->postponed_kill);
+		}
+		return;
+	}
 
 	if (emit_data->inst->Instruction.Opcode == TGSI_OPCODE_KILL_IF)
 		ac_build_kill(&ctx->ac, emit_data->args[0]);
 	else
 		ac_build_kill(&ctx->ac, NULL);
 }
 
 static void emit_icmp(const struct lp_build_tgsi_action *action,
 		      struct lp_build_tgsi_context *bld_base,
 		      struct lp_build_emit_data *emit_data)
-- 
2.7.4



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