RFC for a render API to support adaptive sync and VRR

[Daniel Stone]

Hi,

On 20 April 2018 at 21:32, Manasi Navare <manasi.d.navare at intel.com> wrote:
> On Wed, Apr 18, 2018 at 09:39:02AM +0200, Daniel Vetter wrote:
>> On Wed, Apr 18, 2018 at 5:58 AM, Keith Packard <keithp at keithp.com> wrote:
>> > I'd also encourage using a single unit for all of these values,
>> > preferably nanoseconds. Absolute times should all be referenced to
>> > CLOCK_MONOTONIC.
>>
>> +1 on everything Keith said. I got somehow dragged in khr vk
>> discussions around preventing micro-stuttering, and consensus seems to
>> be that timestamps for scheduling frames is the way to go, most likely
>> absolute ones (not everything is running Linux unfortunately, so can't
>> go outright and claim it's guaranteed to be CLOCK_MONOTONIC).
>
> And yes I also got consensus from Mesa and media folks about using the
> absolute timestamp for scheduling the frames and then the driver will
> modify the vblank logic to "present no earlier than the timestamp"

Whilst we're all piling in, here's another AOL. We didn't yet
implement this for Wayland because of the fun involved in adding a
FIFO mode to a very mailbox window system, but at some point we'll
have to suck it up and push it.

Cheers,
Daniel