[Mesa-dev] [PATCH] radv: do not use CP predication for DCC decompressions

Samuel Pitoiset samuel.pitoiset at gmail.com
Thu Aug 16 16:56:22 UTC 2018

This fixes a regression with some Unity demos. Not sure
what the root cause of the problem is, especially because
the driver doesn't perform any fast color clears. So, it
shouldn't be needed to decompress DCC. RadeonSI says that
the decompression is relatively cheap if the surface has
been decompressed already.

One possible improvement is to two use predicates, one for
DCC and one for FCE that could be cleared when DCC, FMASK
or CMASK are performed by the driver. That might skip some
unnecessary decompression passes (not DCC though).

Fixes: ff7daadca1 ("radv: enable/disable predication for the DCC decompression pass")
CC: 18.2 <mesa-stable at lists.freedesktop.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107563
Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
 src/amd/vulkan/radv_meta_fast_clear.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/amd/vulkan/radv_meta_fast_clear.c b/src/amd/vulkan/radv_meta_fast_clear.c
index f469a9ee8f..b4cc900028 100644
--- a/src/amd/vulkan/radv_meta_fast_clear.c
+++ b/src/amd/vulkan/radv_meta_fast_clear.c
@@ -628,7 +628,7 @@ radv_emit_color_decompress(struct radv_cmd_buffer *cmd_buffer,
                pipeline = cmd_buffer->device->meta_state.fast_clear_flush.cmask_eliminate_pipeline;
-	if (radv_image_has_dcc(image)) {
+	if (!decompress_dcc && radv_image_has_dcc(image)) {
 		old_predicating = cmd_buffer->state.predicating;
 		radv_emit_set_predication_state_from_image(cmd_buffer, image, true);
@@ -696,7 +696,7 @@ radv_emit_color_decompress(struct radv_cmd_buffer *cmd_buffer,
-	if (radv_image_has_dcc(image)) {
+	if (!decompress_dcc && radv_image_has_dcc(image)) {
 		cmd_buffer->state.predicating = old_predicating;
 		radv_emit_set_predication_state_from_image(cmd_buffer, image, false);

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