[Mesa-dev] What use do swap interval > 1 and OML_sync_control divisor and remainder have?

[Bill Spitzak]

 From the Kronos description:

interval is silently clamped to minimum and maximum implementation 
dependent valuesbefore being stored; these values are defined by 
EGLConfig attributes EGL_MIN_SWAP_INTERVAL and EGL_MAX_SWAP_INTERVAL 
respectively.

I think wayland egl can just clamp to 0,1 (or even 1,1 though apparently 
a lot of work has been done to support 0) and this question ignored.

On 01/29/2014 08:33 AM, Alexander E. Patrakov wrote:
> [Just for the sake of argument]
>
> 2014-01-28 Pekka Paalanen <ppaalanen at gmail.com>:
>> Hi Ian and Jason
>>
>> On Mon, 27 Jan 2014 12:26:23 -0700
>> Ian Romanick <idr at freedesktop.org> wrote:
>>> There are a number of theoretical uses, but I don't know that we've
>>> ever seen any in the wild.
>>>
>>> One is video playback.  You likely want 30fps there.
>>
>> I would hope that no video player will use swap interval as a means of
>> target timing, because the buffer queueing protocol I'm planning is
>> supposed to be superior for accurately timed video presentation. The
>> protocol will also be usable with EGL provided content, if the EGL
>> implementation can cope with buffers being reserved by the display
>> server for longer than usual.
>
> One more argument would be that video players actually don't want
> 30fps here, and do that only because of constrained resources. Every
> Smart TV sold nowadays has the motion-interpolation feature, which is
> (unlike frame-doubling, and at least from the viewpoint of some
> people) the proper way to display low-fps content on high-fps panels.
> PC-based video players don't have this feature because nobody so far
> has written the code that works on anything else than NVidia GPUs.
>