ac/surface/gfx6: don't overallocate mipmapped HTILE

Tested-by: Dieter Nützel <Dieter@nuetzel-hh.de>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>

src/amd/common/ac_surface.c

@@ -934,8 +934,17 @@ static int gfx6_compute_surface(ADDR_HANDLE addrlib,
 	/* Make sure HTILE covers the whole miptree, because the shader reads
 	 * TC-compatible HTILE even for levels where it's disabled by DB.
 	 */
-	if (surf->htile_size && config->info.levels > 1)
-		surf->htile_size *= 2;
+	if (surf->htile_size && config->info.levels > 1 &&
+	    surf->flags & RADEON_SURF_TC_COMPATIBLE_HTILE) {
+		/* MSAA can't occur with levels > 1, so ignore the sample count. */
+		const unsigned total_pixels = surf->surf_size / surf->bpe;
+		const unsigned htile_block_size = 8 * 8;
+		const unsigned htile_element_size = 4;
+
+		surf->htile_size = (total_pixels / htile_block_size) *
+				   htile_element_size;
+		surf->htile_size = align(surf->htile_size, surf->htile_alignment);
+	}
 
 	surf->is_linear = surf->u.legacy.level[0].mode == RADEON_SURF_MODE_LINEAR_ALIGNED;
 	surf->is_displayable = surf->is_linear ||