From a77fa227bb0c681eaa0a20476a388c176af4789e Mon Sep 17 00:00:00 2001 From: James Calligeros Date: Wed, 7 Oct 2026 19:33:19 +1000 Subject: [PATCH] drm/fourcc: Add Apple Interchange layout format modifier Apple Interchange is a tiled and compressed image layout used for buffer exchange between Apple hardware blocks. It is similar to the already-supported GPU_TILED_COMPRESSED layout. Add a format modifier for Apple Interchange so that it can be used for buffer exchange. Reviewed-by: Alyssa Rosenzweig Signed-off-by: James Calligeros Signed-off-by: Lyude Paul Link: https://patch.msgid.link/20261007-apple-interchange-modifier-v3-1-721fc44abf6b@gmail.com --- include/uapi/drm/drm_fourcc.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h index a103fdc0b3a3..0bb049f91524 100644 --- a/include/uapi/drm/drm_fourcc.h +++ b/include/uapi/drm/drm_fourcc.h @@ -1626,6 +1626,30 @@ drm_fourcc_canonicalize_nvidia_format_mod(__u64 modifier) #define DRM_FORMAT_MOD_APPLE_GPU_TILED fourcc_mod_code(APPLE, 1) #define DRM_FORMAT_MOD_APPLE_GPU_TILED_COMPRESSED fourcc_mod_code(APPLE, 2) +/* + * Apple Interchange layout + * + * Apple Interchange is a compressed framebuffer format used exclusively for + * sharing buffers between hardware blocks (GPU, display controller, video + * codecs) on Apple platforms. It is similar to and uses the same compression + * scheme as GPU_TILED_COMPRESSED. There is no known uncompressed variant + * of Apple Interchange. + * + * Unlike the GPU layouts, tile size is not dependent on bit depth. RGB + * images and the chroma components of YUV images use 16x16 tiles. The + * luma component of YUV images uses 32x32 tiles. Compression tiles + * are once again 16x16 with 8 bytes of metadata per compression subtile. + * + * Following the example set by GPU_TILED_{,COMPRESSED}, Interchange images + * are treated as a single plane by software and do not have a meaningful + * stride. + * + * AGX has limited support for Apple Interchange. It cannot be used for Z/S + * buffers or array images, for example. It is intended for scanout buffer + * sharing only. + */ +#define DRM_FORMAT_MOD_APPLE_INTERCHANGE fourcc_mod_code(APPLE, 3) + /* * AMD modifiers * -- knotmirror 0.0.1