DRI2 Protocol Spec Draft

[Stephane Marchesin]

On Tue, Sep 9, 2008 at 7:51 PM, Keith Packard <keithp at keithp.com> wrote:
>>  That mechanism could be basically the same as the existing
>> sync-to-vblank mechanisms, but with 'vertical blank' replaced by
>> 'compositing manager screen update'. So it would provide the client with
>> a way to express the display frame at which the buffer swap should take
>> effect and to synchronize to the compositing manager making it so.
>
> We chatted about this and Kristian suggested that we would throttle the
> app to vblank rate, rather than compositing manager rate. On second
> thought, perhaps driving this from the compositing manager would make
> sense.

I think is makes more sense if the composite manager initiates the
vsync because only the composite manager can insert the sync at
coherent points (in the case of single buffering that's useful). Also
this leaves more flexibility for composite managers to act as they
like.

Stephane