On 12/20/2016 07:10 PM, Maarten Lankhorst wrote:
> Op 20-12-16 om 07:23 schreef Archit Taneja:
>>
>>
>> On 12/19/2016 06:20 PM, Maarten Lankhorst wrote:
>>> Op 19-12-16 om 13:08 schreef Archit Taneja:
>>>> This code has been more or less picked up from the vc4 and intel
>>>> implementations of update_plane() funcs for cursor planes.
>>>>
>>>> The update_plane() func is usually the drm_atomic_helper_update_plane
>>>> func that will issue an atomic commit with the plane updates. Such
>>>> commits are not intended to be done faster than the vsync rate.
>>>>
>>>> The legacy cursor userspace API, on the other hand, expects the kernel
>>>> to handle cursor updates immediately.
>>>>
>>>> Create a fast path in update_plane, which updates the cursor registers
>>>> and flushes the configuration. The fast path is taken when there is only
>>>> a change in the cursor's position in the crtc, or a change in the
>>>> cursor's crop co-ordinates. For anything else, we go via the slow path.
>>>>
>>>> We take the slow path even whenever the fb changes, and even when there
>>>> is currently no fb tied to the plane. This should hopefully ensure that
>>>> we always take a slow path for every new fb. The slow path will ensure
>>>> that the fb is prepared/pinned etc.
>>>>
>>>> Cc:
>>>> Signed-off-by: Archit Taneja <architt at codeaurora.org>
>>>> ---
>>>> - Don't know what to do for locking here :/
>>> Shouldn't patch 9 be done first before 8?
>>
>> Patch 9 introduces cursor drm_planes for the first time, so
>> anything done in 8 doesn't really take effect until we add
>> the planes in patch 9. So it's safe to have this order.
> The other way around will allow you to test with the normal atomic helpers 
> first, and then if the hack breaks you're able to bisect it correctly and 
> revert it, that's why I think it should be the other way around. :)

Yeah, makes sense when you put it that way :). Will make sure the hack commit 
comes after
the cursor planes are supported the regular atomic way.

Archit

>
> ~Maarten
>

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