gallium: add PIPE_CAP_PREFER_COMPUTE_BLIT_FOR_MULTIMEDIA

src/gallium/auxiliary/util/u_screen.c

@@ -325,6 +325,7 @@ u_pipe_screen_get_param_defaults(struct pipe_screen *pscreen,
    case PIPE_CAP_TGSI_ATOMFADD:
    case PIPE_CAP_TGSI_SKIP_SHRINK_IO_ARRAYS:
    case PIPE_CAP_IMAGE_LOAD_FORMATTED:
+   case PIPE_CAP_PREFER_COMPUTE_BLIT_FOR_MULTIMEDIA:
       return 0;
 
    case PIPE_CAP_MAX_GS_INVOCATIONS:

src/gallium/docs/source/screen.rst

@@ -521,6 +521,8 @@ The integer capabilities:
   execution. 0 = throttling is disabled.
 * ``PIPE_CAP_DMABUF``: Whether Linux DMABUF handles are supported by
   resource_from_handle and resource_get_handle.
+* ``PIPE_CAP_PREFER_COMPUTE_BLIT_FOR_MULTIMEDIA``: Whether VDPAU, VAAPI, and
+  OpenMAX should use a compute-based blit instead of pipe_context::blit.
 
 .. _pipe_capf:
 

src/gallium/drivers/radeonsi/si_get.c

@@ -155,6 +155,7 @@ static int si_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
 	case PIPE_CAP_TGSI_FS_FBFETCH:
 	case PIPE_CAP_COMPUTE_GRID_INFO_LAST_BLOCK:
 	case PIPE_CAP_IMAGE_LOAD_FORMATTED:
+	case PIPE_CAP_PREFER_COMPUTE_BLIT_FOR_MULTIMEDIA:
 		return 1;
 
 	case PIPE_CAP_RESOURCE_FROM_USER_MEMORY:

src/gallium/include/pipe/p_defines.h

@@ -882,6 +882,7 @@ enum pipe_cap
    PIPE_CAP_IMAGE_LOAD_FORMATTED,
    PIPE_CAP_MAX_FRAMES_IN_FLIGHT,
    PIPE_CAP_DMABUF,
+   PIPE_CAP_PREFER_COMPUTE_BLIT_FOR_MULTIMEDIA,
 };
 
 /**