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

[Daniel Vetter]

On Mon, Apr 25, 2016 at 11:37 AM, Maarten Lankhorst
<maarten.lankhorst at linux.intel.com> wrote:
> 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?

Well uabi renaming train left the station, but internally we can
definitely do that.
s/drm_atomic_async_commit/drm_atomic_nonblocking_commit/ plus
s/async/nonblocking/ in the driver's ->atomic_commit hooks sounds like
a very fine idea. Volunteered?
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch