ac/surface: align DCC size for surfaces that use tile swizzle

Note that dcc_alignment = pipe_interleave_bytes * num_pipes * num_banks,
which is greater than the previous open-coded alignment.

Reviewed-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>

diff --git a/src/amd/common/ac_surface.c b/src/amd/common/ac_surface.c
index 3716d3d..823a65d 100644 (file)
--- a/src/amd/common/ac_surface.c
+++ b/src/amd/common/ac_surface.c
@@ -734,9 +734,16 @@ static int gfx6_compute_surface(ADDR_HANDLE addrlib,
         * complicated.
         */
        if (surf->dcc_size && config->info.levels > 1) {
+               /* The smallest miplevels that are never compressed by DCC
+                * still read the DCC buffer via TC if the base level uses DCC,
+                * and for some reason the DCC buffer needs to be larger if
+                * the miptree uses non-zero tile_swizzle. Otherwise there are
+                * VM faults.
+                *
+                * "dcc_alignment * 4" was determined by trial and error.
+                */
                surf->dcc_size = align64(surf->surf_size >> 8,
-                                        info->pipe_interleave_bytes *
-                                        info->num_tile_pipes);
+                                        surf->dcc_alignment * 4);
        }
 
        /* Make sure HTILE covers the whole miptree, because the shader reads