Re: [PATCH RFC v3 0/7] Async Flip in Atomic ioctl corrections

["Michel Dänzer" <michel.daenzer@mailbox.org>]

On 1/9/26 12:07, Murthy, Arun R wrote:
>> From: Michel Dänzer <michel.daenzer@mailbox.org>
>> On 1/8/26 10:43, Arun R Murthy wrote:
>>> 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.
>>
>> FWIW, this kind of mix'n'match doesn't seem useful with current UAPI, since no
>> new commit can be made for the async plane(s) before the previous commit for
>> the sync plane(s) has completed, so the async plane(s) can't actually have
>> higher update rate than the sync one(s).
> That’s right, such mix and match flips will still consume vblank time for flipping.

Does a plane property really make sense for this then?


> This series doesn’t solve that, but rather accommodate multiple plane async flips in an atomic ioctl and allowing disabling of a sync plane which is already enabled. There has been a long discussion in the gitlab(https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13834) on this.

AFAICT that's a false-positive rejection of commits which don't actually change cursor plane state.


-- 
Earthling Michel Dänzer       \        GNOME / Xwayland / Mesa developer
https://redhat.com             \               Libre software enthusiast