[Mesa-dev] [PATCH 3/6] radeonsi: clear PIPE_IMAGE_ACCESS_WRITE when it's invalid to be on the safe side

[Marek Olšák]

From: Marek Olšák <marek.olsak at amd.com>

---
 src/gallium/drivers/radeonsi/si_descriptors.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/gallium/drivers/radeonsi/si_descriptors.c b/src/gallium/drivers/radeonsi/si_descriptors.c
index 69371ea..471c93a 100644
--- a/src/gallium/drivers/radeonsi/si_descriptors.c
+++ b/src/gallium/drivers/radeonsi/si_descriptors.c
@@ -681,20 +681,28 @@ static void si_set_shader_image_desc(struct si_context *ctx,
 					  view->format,
 					  view->u.buf.offset,
 					  view->u.buf.size, desc);
 		si_set_buf_desc_address(res, view->u.buf.offset, desc + 4);
 	} else {
 		static const unsigned char swizzle[4] = { 0, 1, 2, 3 };
 		struct r600_texture *tex = (struct r600_texture *)res;
 		unsigned level = view->u.tex.level;
 		unsigned width, height, depth, hw_level;
 		bool uses_dcc = vi_dcc_enabled(tex, level);
+		unsigned access = view->access;
+
+		/* Clear the write flag when writes can't occur.
+		 * Note that DCC_DECOMPRESS for MSAA doesn't work in some cases,
+		 * so we don't wanna trigger it.
+		 */
+		if (tex->is_depth || tex->resource.b.b.nr_samples >= 2)
+			access &= ~PIPE_IMAGE_ACCESS_WRITE;
 
 		assert(!tex->is_depth);
 		assert(tex->fmask.size == 0);
 
 		if (uses_dcc && !skip_decompress &&
 		    (view->access & PIPE_IMAGE_ACCESS_WRITE ||
 		     !vi_dcc_formats_compatible(res->b.b.format, view->format))) {
 			/* If DCC can't be disabled, at least decompress it.
 			 * The decompression is relatively cheap if the surface
 			 * has been decompressed already.
-- 
2.7.4