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From: Rob Clark <robdclark@gmail.com>
To: Pekka Paalanen <ppaalanen@gmail.com>
Cc: dri-devel <dri-devel@lists.freedesktop.org>,
	"moderated list:DMA BUFFER SHARING FRAMEWORK"
	<linaro-mm-sig@lists.linaro.org>,
	"Daniel Vetter" <daniel@ffwll.ch>,
	"Christian König" <ckoenig.leichtzumerken@gmail.com>,
	"Michel Dänzer" <michel@daenzer.net>,
	"Rob Clark" <robdclark@chromium.org>,
	"Sumit Semwal" <sumit.semwal@linaro.org>,
	"Gustavo Padovan" <gustavo@padovan.org>,
	"Christian König" <christian.koenig@amd.com>,
	"open list:SYNC FILE FRAMEWORK" <linux-media@vger.kernel.org>,
	"open list" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 8/9] dma-buf/sync_file: Add SET_DEADLINE ioctl
Date: Mon, 27 Sep 2021 07:36:05 -0700	[thread overview]
Message-ID: <CAF6AEGudjfgN+x_KxyED+1XBod7yNqLN43or7vs8h7UKQmzK7Q@mail.gmail.com> (raw)
In-Reply-To: <20210927114201.1f8fdc17@eldfell>

On Mon, Sep 27, 2021 at 1:42 AM Pekka Paalanen <ppaalanen@gmail.com> wrote:
>
> On Fri,  3 Sep 2021 11:47:59 -0700
> Rob Clark <robdclark@gmail.com> wrote:
>
> > From: Rob Clark <robdclark@chromium.org>
> >
> > 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@chromium.org>
> > ---
> >  drivers/dma-buf/sync_file.c    | 19 +++++++++++++++++++
> >  include/uapi/linux/sync_file.h | 20 ++++++++++++++++++++
> >  2 files changed, 39 insertions(+)
> >
> > diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
> > index 394e6e1e9686..f295772d5169 100644
> > --- a/drivers/dma-buf/sync_file.c
> > +++ b/drivers/dma-buf/sync_file.c
> > @@ -459,6 +459,22 @@ static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
> >       return ret;
> >  }
> >
> > +static int sync_file_ioctl_set_deadline(struct sync_file *sync_file,
> > +                                     unsigned long arg)
> > +{
> > +     struct sync_set_deadline ts;
> > +
> > +     if (copy_from_user(&ts, (void __user *)arg, sizeof(ts)))
> > +             return -EFAULT;
> > +
> > +     if (ts.pad)
> > +             return -EINVAL;
> > +
> > +     dma_fence_set_deadline(sync_file->fence, ktime_set(ts.tv_sec, ts.tv_nsec));
> > +
> > +     return 0;
> > +}
> > +
> >  static long sync_file_ioctl(struct file *file, unsigned int cmd,
> >                           unsigned long arg)
> >  {
> > @@ -471,6 +487,9 @@ static long sync_file_ioctl(struct file *file, unsigned int cmd,
> >       case SYNC_IOC_FILE_INFO:
> >               return sync_file_ioctl_fence_info(sync_file, arg);
> >
> > +     case SYNC_IOC_SET_DEADLINE:
> > +             return sync_file_ioctl_set_deadline(sync_file, arg);
> > +
> >       default:
> >               return -ENOTTY;
> >       }
> > 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

BR,
-R

> Also I cannot guess how a compositor should be using this, so
> explaining the expected usage would be really good, with reasons for
> why should userspace bother.
>
>
> Thanks,
> pq
>
> > + */
> > +struct sync_set_deadline {
> > +     __s64   tv_sec;
> > +     __s32   tv_nsec;
> > +     __u32   pad;
> > +};
> > +
> >  #define SYNC_IOC_MAGIC               '>'
> >
> >  /**
> > @@ -95,4 +107,12 @@ struct sync_file_info {
> >   */
> >  #define SYNC_IOC_FILE_INFO   _IOWR(SYNC_IOC_MAGIC, 4, struct sync_file_info)
> >
> > +
> > +/**
> > + * DOC: SYNC_IOC_SET_DEADLINE - set a deadline on a fence
> > + *
> > + * Allows userspace to set a deadline on a fence, see dma_fence_set_deadline()
> > + */
> > +#define SYNC_IOC_SET_DEADLINE        _IOW(SYNC_IOC_MAGIC, 5, struct sync_set_deadline)
> > +
> >  #endif /* _UAPI_LINUX_SYNC_H */
>

  parent reply	other threads:[~2021-09-27 14:31 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-03 18:47 [PATCH v3 0/9] dma-fence: Deadline awareness Rob Clark
2021-09-03 18:47 ` [PATCH v3 1/9] dma-fence: Add deadline awareness Rob Clark
2021-09-08 17:55   ` Daniel Vetter
2021-09-03 18:47 ` [PATCH v3 2/9] drm/vblank: Add helper to get next vblank time Rob Clark
2021-09-03 18:47 ` [PATCH v3 3/9] drm/atomic-helper: Set fence deadline for vblank Rob Clark
2021-09-03 18:47 ` [PATCH v3 4/9] drm/scheduler: Add fence deadline support Rob Clark
2021-09-08 17:45   ` Daniel Vetter
2021-09-09  6:22     ` Christian König
2021-09-14 13:38       ` Daniel Vetter
2021-09-21 15:57     ` Rob Clark
2021-09-21 16:35       ` Rob Clark
2021-09-21 16:45         ` Christian König
2021-09-21 20:09   ` Andrey Grodzovsky
2021-09-21 20:47     ` Rob Clark
2021-09-22  2:18       ` Andrey Grodzovsky
2021-09-22  3:32         ` Rob Clark
2021-09-22 14:31           ` Andrey Grodzovsky
2021-09-22 15:01             ` Rob Clark
2021-09-03 18:47 ` [PATCH v3 5/9] drm/msm: Add deadline based boost support Rob Clark
2021-09-08 17:48   ` Daniel Vetter
2021-09-08 17:57     ` Rob Clark
2021-09-03 18:47 ` [PATCH v3 6/9] dma-buf/fence-array: Add fence deadline support Rob Clark
2021-09-08 18:00   ` Daniel Vetter
2021-09-09  6:55     ` Christian König
2021-09-03 18:47 ` [PATCH v3 7/9] dma-buf/fence-chain: " Rob Clark
2021-09-08 17:54   ` Daniel Vetter
2021-09-08 18:19     ` Rob Clark
2021-09-08 18:45       ` Daniel Vetter
2021-09-09  6:31         ` Christian König
2021-09-03 18:47 ` [PATCH v3 8/9] dma-buf/sync_file: Add SET_DEADLINE ioctl Rob Clark
2021-09-08 17:50   ` Daniel Vetter
2021-09-08 18:23     ` Rob Clark
2021-09-08 18:49       ` Daniel Vetter
2021-09-08 19:40         ` Rob Clark
2021-09-08 21:10           ` Daniel Vetter
2021-09-21 18:08             ` Rob Clark
2021-09-27  8:42   ` Pekka Paalanen
2021-09-27  8:53     ` Christian König
2021-09-27 14:36     ` Rob Clark [this message]
2021-09-28  7:57       ` Pekka Paalanen
2021-09-03 18:48 ` [PATCH v3 9/9] dma-buf/sw_sync: Add fence deadline support Rob Clark
2021-09-09 16:16 ` [PATCH v3 0/9] dma-fence: Deadline awareness Simon Ser
2021-09-09 16:35   ` Rob Clark
2021-09-09 16:42     ` Simon Ser
2021-09-09 17:08       ` Rob Clark

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