Mesa (staging/18.2): radv: do not use CP predication for DCC decompressions

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Module: Mesa
Branch: staging/18.2
Commit: 1e9c4228942a8cf23045938daf333a2b91cd6229
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=1e9c4228942a8cf23045938daf333a2b91cd6229

Author: Samuel Pitoiset <samuel.pitoiset at gmail.com>
Date:   Thu Aug 16 18:56:22 2018 +0200

radv: do not use CP predication for DCC decompressions

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>
Reviewed-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
(cherry picked from commit 0aacb5eab6120aa1410966d23101e16eea3fbcd7)

---

 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 b42a6783fd..74868d5a2b 100644
--- a/src/amd/vulkan/radv_meta_fast_clear.c
+++ b/src/amd/vulkan/radv_meta_fast_clear.c
@@ -603,7 +603,7 @@ 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);
@@ -671,7 +671,7 @@ radv_emit_color_decompress(struct radv_cmd_buffer *cmd_buffer,
 					&cmd_buffer->pool->alloc);
 
 	}
-	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);