drm: document uAPI page-flip flags

Document flags accepted by the page-flip and atomic IOCTLs.

v2 (Pekka):
- Mention DRM_EVENT_FLIP_COMPLETE in DRM_MODE_PAGE_FLIP_EVENT docs.
- Expand DRM_MODE_ATOMIC_NONBLOCK and DRM_MODE_ATOMIC_ALLOW_MODESET
  description.
v3:
- Fix struct field ref syntax (Daniel)
- Clarify when artifacts are no longer displayed (Daniel)
- Add note about sinks deciding to show artifacts on their own (Pekka, Daniel)
v4:
- Fix typo (Pekka)

Signed-off-by: Simon Ser <contact@emersion.fr>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/505107/
This commit is contained in:
Simon Ser 2022-08-24 19:43:42 +02:00
Родитель 96c92551b5
Коммит f633a206ca
1 изменённых файлов: 62 добавлений и 1 удалений

Просмотреть файл

@ -935,12 +935,31 @@ struct hdr_output_metadata {
};
};
/**
* DRM_MODE_PAGE_FLIP_EVENT
*
* Request that the kernel sends back a vblank event (see
* struct drm_event_vblank) with the &DRM_EVENT_FLIP_COMPLETE type when the
* page-flip is done.
*/
#define DRM_MODE_PAGE_FLIP_EVENT 0x01
/**
* DRM_MODE_PAGE_FLIP_ASYNC
*
* Request that the page-flip is performed as soon as possible, ie. with no
* delay due to waiting for vblank. This may cause tearing to be visible on
* the screen.
*/
#define DRM_MODE_PAGE_FLIP_ASYNC 0x02
#define DRM_MODE_PAGE_FLIP_TARGET_ABSOLUTE 0x4
#define DRM_MODE_PAGE_FLIP_TARGET_RELATIVE 0x8
#define DRM_MODE_PAGE_FLIP_TARGET (DRM_MODE_PAGE_FLIP_TARGET_ABSOLUTE | \
DRM_MODE_PAGE_FLIP_TARGET_RELATIVE)
/**
* DRM_MODE_PAGE_FLIP_FLAGS
*
* Bitmask of flags suitable for &drm_mode_crtc_page_flip_target.flags.
*/
#define DRM_MODE_PAGE_FLIP_FLAGS (DRM_MODE_PAGE_FLIP_EVENT | \
DRM_MODE_PAGE_FLIP_ASYNC | \
DRM_MODE_PAGE_FLIP_TARGET)
@ -1034,11 +1053,53 @@ struct drm_mode_destroy_dumb {
__u32 handle;
};
/* page-flip flags are valid, plus: */
/**
* DRM_MODE_ATOMIC_TEST_ONLY
*
* Do not apply the atomic commit, instead check whether the hardware supports
* this configuration.
*
* See &drm_mode_config_funcs.atomic_check for more details on test-only
* commits.
*/
#define DRM_MODE_ATOMIC_TEST_ONLY 0x0100
/**
* DRM_MODE_ATOMIC_NONBLOCK
*
* Do not block while applying the atomic commit. The &DRM_IOCTL_MODE_ATOMIC
* IOCTL returns immediately instead of waiting for the changes to be applied
* in hardware. Note, the driver will still check that the update can be
* applied before retuning.
*/
#define DRM_MODE_ATOMIC_NONBLOCK 0x0200
/**
* DRM_MODE_ATOMIC_ALLOW_MODESET
*
* Allow the update to result in temporary or transient visible artifacts while
* the update is being applied. Applying the update may also take significantly
* more time than a page flip. All visual artifacts will disappear by the time
* the update is completed, as signalled through the vblank event's timestamp
* (see struct drm_event_vblank).
*
* This flag must be set when the KMS update might cause visible artifacts.
* Without this flag such KMS update will return a EINVAL error. What kind of
* update may cause visible artifacts depends on the driver and the hardware.
* User-space that needs to know beforehand if an update might cause visible
* artifacts can use &DRM_MODE_ATOMIC_TEST_ONLY without
* &DRM_MODE_ATOMIC_ALLOW_MODESET to see if it fails.
*
* To the best of the driver's knowledge, visual artifacts are guaranteed to
* not appear when this flag is not set. Some sinks might display visual
* artifacts outside of the driver's control.
*/
#define DRM_MODE_ATOMIC_ALLOW_MODESET 0x0400
/**
* DRM_MODE_ATOMIC_FLAGS
*
* Bitfield of flags accepted by the &DRM_IOCTL_MODE_ATOMIC IOCTL in
* &drm_mode_atomic.flags.
*/
#define DRM_MODE_ATOMIC_FLAGS (\
DRM_MODE_PAGE_FLIP_EVENT |\
DRM_MODE_PAGE_FLIP_ASYNC |\