radeonsi/gfx9: add a temporary workaround for a tessellation driver bug

The workaround will do for now. The root cause is still unknown.

This fixes new piglit: 16in-1out

Cc: 17.1 17.2 <mesa-stable@lists.freedesktop.org>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>

diff --git a/src/gallium/drivers/radeonsi/si_state_draw.c b/src/gallium/drivers/radeonsi/si_state_draw.c
index 9631f18ff7f7f9e36f8390385012760eeecbfc77..cb9bbd20805bf2007f3747664b57817d1c1bdfe3 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_state_draw.c
+++ b/src/gallium/drivers/radeonsi/si_state_draw.c
@@ -195,7 +195,11 @@ static void si_emit_derived_tess_state(struct si_context *sctx,
         */
        *num_patches = MIN2(*num_patches, 40);
 
-       if (sctx->b.chip_class == SI) {
+       if (sctx->b.chip_class == SI ||
+           /* TODO: fix GFX9 where a threadgroup contains more than 1 wave and
+            * LS vertices per patch > HS vertices per patch. Piglit: 16in-1out */
+           (sctx->b.chip_class == GFX9 &&
+            num_tcs_input_cp > num_tcs_output_cp)) {
                /* SI bug workaround, related to power management. Limit LS-HS
                 * threadgroups to only one wave.
                 */