The one big missing piece here is how strides are defined. I assume from context it's the same convention as GPU_TILED_COMPRESSED but this should probably be spelled out.
Just adding a sentence "Strides follow the same convention as DRM_FORMAT_MOD_APPLE_GPU_TILED." should be enough to define the uAPI unambiguously here. With that it will be Reviewed-by: Alyssa Rosenzweig <[email protected]> Le Sun, Oct 04, 2026 at 10:42:29PM +1000, James Calligeros a écrit : > 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. > > Signed-off-by: James Calligeros <[email protected]> > --- > Changes in v2: > - Fix typo > - Link to v1: > https://patch.msgid.link/[email protected] > > To: Maarten Lankhorst <[email protected]> > To: Maxime Ripard <[email protected]> > To: Thomas Zimmermann <[email protected]> > To: David Airlie <[email protected]> > To: Simona Vetter <[email protected]> > Cc: [email protected] > Cc: [email protected] > --- > include/uapi/drm/drm_fourcc.h | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h > index a103fdc0b3a3..d304ee5c614c 100644 > --- a/include/uapi/drm/drm_fourcc.h > +++ b/include/uapi/drm/drm_fourcc.h > @@ -1626,6 +1626,26 @@ 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. > + * > + * 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 > * > > --- > base-commit: 08dbfad3f5040f5bdb6c529da20d6d4e81fefd72 > change-id: 20260830-apple-interchange-modifier-cbcc311c835d > > Best regards, > -- > James Calligeros <[email protected]> >
