On Mon, 27 Sep 2021 07:36:05 -0700
Rob Clark <robdclark@xxxxxxxxx> wrote:
> On Mon, Sep 27, 2021 at 1:42 AM Pekka Paalanen <ppaalanen@xxxxxxxxx> wrote:
> >
> > On Fri, 3 Sep 2021 11:47:59 -0700
> > Rob Clark <robdclark@xxxxxxxxx> wrote:
> >
> > > From: Rob Clark <robdclark@xxxxxxxxxxxx>
> > >
> > > The initial purpose is for igt tests, but this would also be useful for
> > > compositors that wait until close to vblank deadline to make decisions
> > > about which frame to show.
> > >
> > > Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
> > > ---
> > > drivers/dma-buf/sync_file.c | 19 +++++++++++++++++++
> > > include/uapi/linux/sync_file.h | 20 ++++++++++++++++++++
> > > 2 files changed, 39 insertions(+)
...
> > > diff --git a/include/uapi/linux/sync_file.h b/include/uapi/linux/sync_file.h
> > > index ee2dcfb3d660..f67d4ffe7566 100644
> > > --- a/include/uapi/linux/sync_file.h
> > > +++ b/include/uapi/linux/sync_file.h
> > > @@ -67,6 +67,18 @@ struct sync_file_info {
> > > __u64 sync_fence_info;
> > > };
> > >
> > > +/**
> > > + * struct sync_set_deadline - set a deadline on a fence
> > > + * @tv_sec: seconds elapsed since epoch
> > > + * @tv_nsec: nanoseconds elapsed since the time given by the tv_sec
> > > + * @pad: must be zero
> >
> > Hi Rob,
> >
> > I think you need to specify which clock this timestamp must be in.
> >
> > Which epoch? Sounds a bit like CLOCK_REALTIME to me which would not
> > make sense.
>
> It should be monotonic.. same clock as is used for vblank timestamps,
> which I assume that would be the most straightforward thing for
> compositors to use
Yes, it would. Just need to document that. :-)
Thanks,
pq
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