radeonsi: simplify CB_TARGET_MASK logic

we can now rely on CB_COLORn_INFO to disable empty slots.

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

diff --git a/src/gallium/drivers/radeonsi/si_state.c b/src/gallium/drivers/radeonsi/si_state.c
index a44f977..8d9fe53 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_state.c
+++ b/src/gallium/drivers/radeonsi/si_state.c
@@ -88,27 +88,20 @@ static unsigned si_pack_float_12p4(float x)
 /*
  * Inferred framebuffer and blender state.
  *
- * One of the reasons CB_TARGET_MASK must be derived from the framebuffer state
- * is that:
- * - The blend state mask is 0xf most of the time.
- * - The COLOR1 format isn't INVALID because of possible dual-source blending,
- *   so COLOR1 is enabled pretty much all the time.
- * So CB_TARGET_MASK is the only register that can disable COLOR1.
- *
- * Another reason is to avoid a hang with dual source blending.
+ * CB_TARGET_MASK is emitted here to avoid a hang with dual source blending
+ * if there is not enough PS outputs.
  */
 static void si_emit_cb_render_state(struct si_context *sctx, struct r600_atom *atom)
 {
        struct radeon_winsys_cs *cs = sctx->b.gfx.cs;
        struct si_state_blend *blend = sctx->queued.named.blend;
-       uint32_t cb_target_mask = 0, i;
-
-       for (i = 0; i < sctx->framebuffer.state.nr_cbufs; i++)
-               if (sctx->framebuffer.state.cbufs[i])
-                       cb_target_mask |= 0xf << (4*i);
+       uint32_t cb_target_mask, i;
 
+       /* CB_COLORn_INFO.FORMAT=INVALID disables empty colorbuffer slots. */
        if (blend)
-               cb_target_mask &= blend->cb_target_mask;
+               cb_target_mask = blend->cb_target_mask;
+       else
+               cb_target_mask = 0xffffffff;
 
        /* Avoid a hang that happens when dual source blending is enabled
         * but there is not enough color outputs. This is undefined behavior,