radeonsi: disable SPI color outputs the shader doesn't write

Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>

diff --git a/src/gallium/drivers/radeonsi/si_shader.h b/src/gallium/drivers/radeonsi/si_shader.h
index f49290a..50375e2 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_shader.h
+++ b/src/gallium/drivers/radeonsi/si_shader.h
@@ -213,6 +213,10 @@ struct si_shader_selector {
 
        /* PS parameters. */
        unsigned        db_shader_control;
+       /* Set 0xf or 0x0 (4 bits) per each written output.
+        * ANDed with spi_shader_col_format.
+        */
+       unsigned        colors_written_4bit;
 
        /* masks of "get_unique_index" bits */
        uint64_t        outputs_written;

diff --git a/src/gallium/drivers/radeonsi/si_state_shaders.c b/src/gallium/drivers/radeonsi/si_state_shaders.c
index 59aee54..79f2335 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_state_shaders.c
+++ b/src/gallium/drivers/radeonsi/si_state_shaders.c
@@ -647,6 +647,12 @@ static inline void si_shader_selector_key(struct pipe_context *ctx,
                if (sctx->b.chip_class <= CIK && sctx->b.family != CHIP_HAWAII)
                        key->ps.color_is_int8 = sctx->framebuffer.color_is_int8;
 
+               /* Disable unwritten outputs (if WRITE_ALL_CBUFS isn't enabled). */
+               if (!key->ps.last_cbuf) {
+                       key->ps.spi_shader_col_format &= sel->colors_written_4bit;
+                       key->ps.color_is_int8 &= sel->info.colors_written;
+               }
+
                if (rs) {
                        bool is_poly = (sctx->current_rast_prim >= PIPE_PRIM_TRIANGLES &&
                                        sctx->current_rast_prim <= PIPE_PRIM_POLYGON) ||
@@ -831,6 +837,12 @@ static void *si_create_shader_selector(struct pipe_context *ctx,
                }
                sel->esgs_itemsize = util_last_bit64(sel->outputs_written) * 16;
                break;
+
+       case PIPE_SHADER_FRAGMENT:
+               for (i = 0; i < 8; i++)
+                       if (sel->info.colors_written & (1 << i))
+                               sel->colors_written_4bit |= 0xf << (4 * i);
+               break;
        }
 
        /* DB_SHADER_CONTROL */