[Mesa-dev] [PATCH 06/10] radeonsi: disable RB+ blend optimizations for dual source blending

[Marek Olšák]

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

---
 src/gallium/drivers/radeonsi/si_state.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/gallium/drivers/radeonsi/si_state.c b/src/gallium/drivers/radeonsi/si_state.c
index 911e979..1ccf5b6 100644
--- a/src/gallium/drivers/radeonsi/si_state.c
+++ b/src/gallium/drivers/radeonsi/si_state.c
@@ -550,20 +550,31 @@ static void *si_create_blend_state_mode(struct pipe_context *ctx,
 			blend->need_src_alpha_4bit |= 0xfu << (i * 4);
 	}
 
 	if (blend->cb_target_mask) {
 		color_control |= S_028808_MODE(mode);
 	} else {
 		color_control |= S_028808_MODE(V_028808_CB_DISABLE);
 	}
 
 	if (sctx->b.family == CHIP_STONEY) {
+		/* Disable RB+ blend optimizations for dual source blending.
+		 * Vulkan does this.
+		 */
+		if (blend->dual_src_blend) {
+			for (int i = 0; i < 8; i++) {
+				sx_mrt_blend_opt[i] =
+					S_028760_COLOR_COMB_FCN(V_028760_OPT_COMB_NONE) |
+					S_028760_ALPHA_COMB_FCN(V_028760_OPT_COMB_NONE);
+			}
+		}
+
 		for (int i = 0; i < 8; i++)
 			si_pm4_set_reg(pm4, R_028760_SX_MRT0_BLEND_OPT + i * 4,
 				       sx_mrt_blend_opt[i]);
 
 		/* RB+ doesn't work with dual source blending, logic op, and RESOLVE. */
 		if (blend->dual_src_blend || state->logicop_enable ||
 		    mode == V_028808_CB_RESOLVE)
 			color_control |= S_028808_DISABLE_DUAL_QUAD(1);
 	}
 
-- 
2.7.4