[PATCH] drm/amd/display: Add fast path for cursor plane updates

[Grodzovsky, Andrey]

Ok - the change is Acked-by: Andrey Grodzovsky <andrey.grodzovsky at amd.com>

Andrey


On 12/06/2018 10:59 AM, Nicholas Kazlauskas wrote:
> On 2018-12-06 10:36 a.m., Grodzovsky, Andrey wrote:
>> Not an expert on Freesync so maybe stupid question but from he comment
>> looks like this pipe locking is only for the sake of Freesync mode there
>> - why is it then called unconditionally w/o checking if you even run in
>> Freesync mode ?
>>
>> Andrey
> I don't think there's any sort of state tracking done in DC for FreeSync
> state changes on a stream so it was probably easier to do this. Given
> the age of the pipe lock addition I would be worried about other
> behavior relying on it now if it was just conditionally done on that.
>
> In practice I think the worst case effect of guarding these calls with a
> mutex is <100us of delay. That's for two separate threads issuing two
> commits at the same time with the planes changed.
>
> Nicholas Kazlauskas
>
>>
>> On 12/06/2018 08:42 AM, Kazlauskas, Nicholas wrote:
>>> A reader/writer lock wouldn't help here, actually.
>>>
>>> Fast updates (and page flips in particular) need to lock the pipe as
>>> well, see: commit_planes_for_stream.
>>>
>>> Nicholas Kazlauskas
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