struct drm_crtc_state {
/**
* @async_flip:
*
* This is set when DRM_MODE_PAGE_FLIP_ASYNC is set in the legacy
* PAGE_FLIP IOCTL. It's not wired up for the atomic IOCTL
itself yet.
*/
bool async_flip;
In the existing code the flag async_flip was intended for the legacy
PAGE_FLIP IOCTL. But the same is being used for atomic IOCTL.
As per the hardware feature is concerned, async flip is a plane feature
and is to be treated per plane basis and not per pipe basis.
For a given hardware pipe, among the multiple hardware planes, one can
go with sync flip and other 2/3 can go with async flip.
Tearing affect will be noticed with this and if any policy should be
taken care by the user space. KMD not to include any policy
as to allow async on only one plane for a given pipe as all policy done
in user and KMD exposes what is supported by the hardware.
There would be a bunch of changes to correct this in the atomic path.
Add a new async_flip plane property to allow user enable async flip on
the required plane.
Any restriction checks for async_flip will be taken in atomic_check()
and not in the atomic_ioctl().
Let the preset code reside as is even in the atomic patch until all the
existing drivers and user space implementations move to plane property
for async flips.
Changes include removal of the checks we have in atomic path so as to
reject any changes(different plane, pipe, connector) along with async
flip. This would be replaced with checks so as to reject any change in
that particular plane where async is enabled(reject any change in
pipe/connector as that would have impact on this plane)
With the above changes, the challenge that we have presently so as to
enable async flip on overlays which is handled seperately with if
condition in drm_atomic_uapi.c can be moved to driver specific
atomic_check code.
This series depicts the changes in the drm core and upon getting
feedback on this, driver specific changes for theis will be done in the
next revision on the same series.
Please let us know your opinion on this.
Thanks and Regards,
Arun R Murthy
-------------
Signed-off-by: Arun R Murthy <[email protected]>
---
Arun R Murthy (2):
drm/atomic/plane: Add plane property for async flip
drm/atomic: Use async_flip plane property for asynchronous flips
drivers/gpu/drm/drm_atomic_uapi.c | 22 ++++++++++++++++++++++
drivers/gpu/drm/drm_plane.c | 31 +++++++++++++++++++++++++++++++
include/drm/drm_plane.h | 12 ++++++++++++
3 files changed, 65 insertions(+)
---
base-commit: ac65b2261663d50cc761c94a40b6093ee714e62f
change-id: 20251010-async-feb09912440b
Best regards,
--
Arun R Murthy <[email protected]>
