[Intel-gfx] [PATCH] drm/atomic: Always allow async support for the atomic ioctl.

[Maarten Lankhorst]

Op 25-04-16 om 11:35 schreef Daniel Vetter:
> On Mon, Apr 25, 2016 at 11:21 AM, Maarten Lankhorst
> <maarten.lankhorst at linux.intel.com> wrote:
>> async_page_flip is a unrelated flag and should not be used for
>> testing support. It's up to the drivers to fail if they don't
>> support async commit.
>>
>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Once more (summary of our irc discussion):
>
> - DRM_MODE_PAGE_FLIP_ASYNC = flipping with tearing, i.e. not vblank
> synced. Gives you lower latency and unrestricted rendering, aka
> benchmark mode. Needs special hw support and on intel only supported
> on the primary plane. I think a better way to almost get all the
> benefits of async by simply implementing a queue of flips that all get
> collapsed to the next vblank.
>
> - async atomic commit = non-blocking ioctl.
>
> Two entirely orthogonal things (you could do blocking atomic commit
> with async flip, but doesn't make much sense).
>
> Maybe instead we need a better documentation for the FLIP_ASYNC flag?
>
yeah it's confusing, especially with atomic async commit. Maybe rename to nonblocking commit?

~Maarten