Mesa (master): radeonsi: apply a tessellation bug workaround for SI

[Marek Olšák]

Module: Mesa
Branch: master
Commit: 78c4528ae7709fbe94d917d034cfd60535b5dcf3
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=78c4528ae7709fbe94d917d034cfd60535b5dcf3

Author: Marek Olšák <marek.olsak at amd.com>
Date:   Tue Nov 29 20:41:23 2016 +0100

radeonsi: apply a tessellation bug workaround for SI

Cc: 13.0 <mesa-stable at lists.freedesktop.org>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle at amd.com>

---

 src/gallium/drivers/radeonsi/si_state_draw.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/gallium/drivers/radeonsi/si_state_draw.c b/src/gallium/drivers/radeonsi/si_state_draw.c
index 10073ef..cba5a03 100644
--- a/src/gallium/drivers/radeonsi/si_state_draw.c
+++ b/src/gallium/drivers/radeonsi/si_state_draw.c
@@ -166,6 +166,13 @@ static void si_emit_derived_tess_state(struct si_context *sctx,
 	 * specific value is taken from the proprietary driver.
 	 */
 	*num_patches = MIN2(*num_patches, 40);
+
+	/* SI bug workaround - limit LS-HS threadgroups to only one wave. */
+	if (sctx->b.chip_class == SI) {
+		unsigned one_wave = 64 / MAX2(num_tcs_input_cp, num_tcs_output_cp);
+		*num_patches = MIN2(*num_patches, one_wave);
+	}
+
 	sctx->last_num_patches = *num_patches;
 
 	output_patch0_offset = input_patch_size * *num_patches;