[Mesa-dev] [PATCH 2/2] radeonsi/gfx9: fix gl_ViewportIndex

[Marek Olšák]

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

Cc: 17.1 <mesa-stable at lists.freedesktop.org>
---
 src/gallium/drivers/radeonsi/si_shader.c        | 43 +++++++++++++++++++++----
 src/gallium/drivers/radeonsi/si_state_shaders.c | 13 ++++++--
 2 files changed, 48 insertions(+), 8 deletions(-)

diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index aa5ba8d..f19073d 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -2374,22 +2374,22 @@ handle_semantic:
 		pos_args[0].out[3] = base->one;  /* W */
 	}
 
 	/* Write the misc vector (point size, edgeflag, layer, viewport). */
 	if (shader->selector->info.writes_psize ||
 	    shader->selector->info.writes_edgeflag ||
 	    shader->selector->info.writes_viewport_index ||
 	    shader->selector->info.writes_layer) {
 		pos_args[1].enabled_channels = shader->selector->info.writes_psize |
 					       (shader->selector->info.writes_edgeflag << 1) |
-					       (shader->selector->info.writes_layer << 2) |
-					       (shader->selector->info.writes_viewport_index << 3);
+					       (shader->selector->info.writes_layer << 2);
+
 		pos_args[1].valid_mask = 0; /* EXEC mask */
 		pos_args[1].done = 0; /* last export? */
 		pos_args[1].target = V_008DFC_SQ_EXP_POS + 1;
 		pos_args[1].compr = 0; /* COMPR flag */
 		pos_args[1].out[0] = base->zero; /* X */
 		pos_args[1].out[1] = base->zero; /* Y */
 		pos_args[1].out[2] = base->zero; /* Z */
 		pos_args[1].out[3] = base->zero; /* W */
 
 		if (shader->selector->info.writes_psize)
@@ -2404,25 +2404,56 @@ handle_semantic:
 			edgeflag_value = lp_build_min(&bld_base->int_bld,
 						      edgeflag_value,
 						      ctx->i32_1);
 
 			/* The LLVM intrinsic expects a float. */
 			pos_args[1].out[1] = LLVMBuildBitCast(ctx->gallivm.builder,
 							  edgeflag_value,
 							  ctx->f32, "");
 		}
 
-		if (shader->selector->info.writes_layer)
-			pos_args[1].out[2] = layer_value;
+		if (ctx->screen->b.chip_class >= GFX9) {
+			/* GFX9 has the layer in out.z[10:0] and the viewport
+			 * index in out.z[19:16].
+			 */
+			if (shader->selector->info.writes_layer) {
+				LLVMValueRef v = layer_value;
+
+				v = bitcast(bld_base, TGSI_TYPE_UNSIGNED, v);
+				v = LLVMBuildAnd(ctx->gallivm.builder, v,
+						 LLVMConstInt(ctx->i32, 0x7ff, 0), "");
+				pos_args[1].out[2] = bitcast(bld_base, TGSI_TYPE_FLOAT, v);
+			}
+
+			if (shader->selector->info.writes_viewport_index) {
+				LLVMValueRef v = viewport_index_value;
+
+				v = bitcast(bld_base, TGSI_TYPE_UNSIGNED, v);
+				v = LLVMBuildAnd(ctx->gallivm.builder, v,
+						 LLVMConstInt(ctx->i32, 0xf, 0), "");
+				v = LLVMBuildShl(ctx->gallivm.builder, v,
+						 LLVMConstInt(ctx->i32, 16, 0), "");
+				v = LLVMBuildOr(ctx->gallivm.builder, v,
+						bitcast(bld_base, TGSI_TYPE_UNSIGNED,
+						        pos_args[1].out[2]), "");
+				pos_args[1].out[2] = bitcast(bld_base, TGSI_TYPE_FLOAT, v);
+				pos_args[1].enabled_channels |= 1 << 2;
+			}
+		} else {
+			if (shader->selector->info.writes_layer)
+				pos_args[1].out[2] = layer_value;
 
-		if (shader->selector->info.writes_viewport_index)
-			pos_args[1].out[3] = viewport_index_value;
+			if (shader->selector->info.writes_viewport_index) {
+				pos_args[1].out[3] = viewport_index_value;
+				pos_args[1].enabled_channels |= 1 << 3;
+			}
+		}
 	}
 
 	for (i = 0; i < 4; i++)
 		if (pos_args[i].out[0])
 			shader->info.nr_pos_exports++;
 
 	pos_idx = 0;
 	for (i = 0; i < 4; i++) {
 		if (!pos_args[i].out[0])
 			continue;
diff --git a/src/gallium/drivers/radeonsi/si_state_shaders.c b/src/gallium/drivers/radeonsi/si_state_shaders.c
index a5260f5..8c09ff1 100644
--- a/src/gallium/drivers/radeonsi/si_state_shaders.c
+++ b/src/gallium/drivers/radeonsi/si_state_shaders.c
@@ -850,22 +850,31 @@ static void si_shader_vs(struct si_screen *sscreen, struct si_shader *shader,
 		return;
 
 	/* We always write VGT_GS_MODE in the VS state, because every switch
 	 * between different shader pipelines involving a different GS or no
 	 * GS at all involves a switch of the VS (different GS use different
 	 * copy shaders). On the other hand, when the API switches from a GS to
 	 * no GS and then back to the same GS used originally, the GS state is
 	 * not sent again.
 	 */
 	if (!gs) {
-		si_pm4_set_reg(pm4, R_028A40_VGT_GS_MODE,
-			       S_028A40_MODE(enable_prim_id ? V_028A40_GS_SCENARIO_A : 0));
+		unsigned mode = 0;
+
+		/* PrimID needs GS scenario A.
+		 * GFX9 also needs it when ViewportIndex is enabled.
+		 */
+		if (enable_prim_id ||
+		    (sscreen->b.chip_class >= GFX9 &&
+		     shader->selector->info.writes_viewport_index))
+			mode = V_028A40_GS_SCENARIO_A;
+
+		si_pm4_set_reg(pm4, R_028A40_VGT_GS_MODE, S_028A40_MODE(mode));
 		si_pm4_set_reg(pm4, R_028A84_VGT_PRIMITIVEID_EN, enable_prim_id);
 	} else {
 		si_pm4_set_reg(pm4, R_028A40_VGT_GS_MODE, si_vgt_gs_mode(gs));
 		si_pm4_set_reg(pm4, R_028A84_VGT_PRIMITIVEID_EN, 0);
 	}
 
 	va = shader->bo->gpu_address;
 	si_pm4_add_bo(pm4, shader->bo, RADEON_USAGE_READ, RADEON_PRIO_SHADER_BINARY);
 
 	if (gs) {
-- 
2.7.4