Commit 60687716 authored by Simon Ser's avatar Simon Ser
Browse files

drm: document DRM_IOCTL_PRIME_HANDLE_TO_FD and PRIME_FD_TO_HANDLE 



v2: mention caps, note that the IOCTLs might fail, document that
user-space needs a data structure to keep track of the
handles (Daniel V.)

Signed-off-by: default avatarSimon Ser <contact@emersion.fr>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Pekka Paalanen <ppaalanen@gmail.com>
Cc: Daniel Stone <daniel@fooishbar.org>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: default avatarPekka Paalanen <pekka.paalanen@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230217162151.59996-2-contact@emersion.fr
parent 61a55f8b

include/uapi/drm/drm.h

+30 −0
Original line number Diff line number Diff line
@@ -1025,7 +1025,37 @@ extern "C" { 
#define DRM_IOCTL_UNLOCK		DRM_IOW( 0x2b, struct drm_lock)

#define DRM_IOCTL_FINISH		DRM_IOW( 0x2c, struct drm_lock)



/**

 * DRM_IOCTL_PRIME_HANDLE_TO_FD - Convert a GEM handle to a DMA-BUF FD.

 *

 * User-space sets &drm_prime_handle.handle with the GEM handle to export and

 * &drm_prime_handle.flags, and gets back a DMA-BUF file descriptor in

 * &drm_prime_handle.fd.

 *

 * The export can fail for any driver-specific reason, e.g. because export is

 * not supported for this specific GEM handle (but might be for others).

 *

 * Support for exporting DMA-BUFs is advertised via &DRM_PRIME_CAP_EXPORT.

 */

#define DRM_IOCTL_PRIME_HANDLE_TO_FD    DRM_IOWR(0x2d, struct drm_prime_handle)

/**

 * DRM_IOCTL_PRIME_FD_TO_HANDLE - Convert a DMA-BUF FD to a GEM handle.

 *

 * User-space sets &drm_prime_handle.fd with a DMA-BUF file descriptor to

 * import, and gets back a GEM handle in &drm_prime_handle.handle.

 * &drm_prime_handle.flags is unused.

 *

 * If an existing GEM handle refers to the memory object backing the DMA-BUF,

 * that GEM handle is returned. Therefore user-space which needs to handle

 * arbitrary DMA-BUFs must have a user-space lookup data structure to manually

 * reference-count duplicated GEM handles. For more information see

 * &DRM_IOCTL_GEM_CLOSE.

 *

 * The import can fail for any driver-specific reason, e.g. because import is

 * only supported for DMA-BUFs allocated on this DRM device.

 *

 * Support for importing DMA-BUFs is advertised via &DRM_PRIME_CAP_IMPORT.

 */

#define DRM_IOCTL_PRIME_FD_TO_HANDLE    DRM_IOWR(0x2e, struct drm_prime_handle)



#define DRM_IOCTL_AGP_ACQUIRE		DRM_IO(  0x30)