Re: [PATCH [RFC] v3 5/7] drm/atomic: Allow planes with NULL fb along with async flip

["Murthy, Arun R" <arun.r.murthy@intel.com>]

On 12-01-2026 16:54, Michel Dänzer wrote:
> On 1/12/26 09:26, Murthy, Arun R wrote:
>> On 09-01-2026 16:53, Michel Dänzer wrote:
>>> On 1/9/26 12:08, Murthy, Arun R wrote:
>>>>> From: Michel Dänzer <michel.daenzer@mailbox.org>
>>>>> On 1/8/26 10:43, Arun R Murthy wrote:
>>>>>> Along with async flip if there is a request to disable a sync plane by
>>>>>> providing a NULL fb allow them.
>>>>> That could result in async changes to other planes taking effect in an earlier
>>>>> refresh cycle than the sync plane being disabled, couldn't it? In which case the
>>>>> commit arguably wouldn't actually be "atomic".
>>>>>
>>>> This is the request from the community to allow disabling of a sync plane in an async flip atomic ioctl.
>>>> https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13834
>>> Can't see any such request there. I suspect there might be a misunderstanding.
>> Here cursor is a sync flip.
>> https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13834#note_2855843
> Not sure what you mean.
>
> The cursor plane is disabled in KWin's atomic commits with DRM_MODE_PAGE_FLIP_ASYNC, so it's irrelevant for them.
>
> In the comment following the one you referenced, Xaver (one of the main KWin developers) agreed that KWin not setting DRM_MODE_PAGE_FLIP_ASYNC in the commit which disables the cursor plane is fine.
>
> I see no request for being able to mix sync & async plane updates in a single commit.
>
Sorry maybe I might be creating more confusion or my words are not 
giving clarity.

Let me try to put it in simple words.
The 
comment(https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13834#note_2857640) 
from Xaver says that disabling of cursor plane along with a sync flip 
should work.
Uma in the 
comment(https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13834#note_2863599) 
has acknowledged the changes.

Thanks and Regards,
Arun R Murthy
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