On Tue, Feb 28, 2023 at 1:22 AM Pekka Paalanen wrote:
>
> On Mon, 27 Feb 2023 11:35:11 -0800
> Rob Clark wrote:
>
> > From: Rob Clark
> >
> > 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.
> >
> > The igt tests can be found at:
> >
> > https://gitlab.freedesktop.org/robclark/igt-gpu-tools/-/commits/fence-deadline
> >
> > v2: Clarify the timebase, add link to igt tests
> > v3: Use u64 value in ns to express deadline.
> > v4: More doc
> >
> > Signed-off-by: Rob Clark
> > ---
> > drivers/dma-buf/dma-fence.c| 3 ++-
> > drivers/dma-buf/sync_file.c| 19 +++
> > include/uapi/linux/sync_file.h | 22 ++
> > 3 files changed, 43 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
> > index e103e821d993..7761ceeae620 100644
> > --- a/drivers/dma-buf/dma-fence.c
> > +++ b/drivers/dma-buf/dma-fence.c
> > @@ -933,7 +933,8 @@ EXPORT_SYMBOL(dma_fence_wait_any_timeout);
> > * the GPU's devfreq to reduce frequency, when in fact the opposite is
> > what is
> > * needed.
> > *
> > - * To this end, deadline hint(s) can be set on a _fence via
> > _fence_set_deadline.
> > + * To this end, deadline hint(s) can be set on a _fence via
> > _fence_set_deadline
> > + * (or indirectly via userspace facing ioctls like _IOC_SET_DEADLINE).
> > * The deadline hint provides a way for the waiting driver, or userspace,
> > to
> > * convey an appropriate sense of urgency to the signaling driver.
>
> Hi,
>
> when the kernel HTML doc is generated, I assume the above becomes a
> link to "DOC: SYNC_IOC_SET_DEADLINE - set a deadline on a fence", right?
Heh, kernel docs completely miss the sync_file uABI.. I'll add a patch
to correct that in order to make these links work properly.
BR,
-R
> > *
> > diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
> > index af57799c86ce..418021cfb87c 100644
> > --- a/drivers/dma-buf/sync_file.c
> > +++ b/drivers/dma-buf/sync_file.c
> > @@ -350,6 +350,22 @@ 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(, (void __user *)arg, sizeof(ts)))
> > + return -EFAULT;
> > +
> > + if (ts.pad)
> > + return -EINVAL;
> > +
> > + dma_fence_set_deadline(sync_file->fence, ns_to_ktime(ts.deadline_ns));
> > +
> > + return 0;
> > +}
> > +
> > static long sync_file_ioctl(struct file *file, unsigned int cmd,
> > unsigned long arg)
> > {
> > @@ -362,6 +378,9 @@ 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..49325cf6749b 100644
> > --- a/include/uapi/linux/sync_file.h
> > +++ b/include/uapi/linux/sync_file.h
> > @@ -67,6 +67,21 @@ struct sync_file_info {
> > __u64 sync_fence_info;
> > };
> >
> > +/**
> > + * struct sync_set_deadline - set a deadline hint on a fence
> > + * @deadline_ns: absolute time of the deadline
>
> Is it legal to pass zero as deadline_ns?
>
> > + * @pad: must be zero
> > + *
> > + * The timebase for the deadline is CLOCK_MONOTONIC (same as vblank)
>
> Does something here provide doc links to "DOC: SYNC_IOC_SET_DEADLINE -
> set a deadline on a fence" and to the "DOC: deadline hints"?
>
> > + */
> > +struct sync_set_deadline {
> > + __u64 deadline_ns;
> > + /* Not strictly needed for alignment but gives some possibility
> > + * for future extension:
> > + */
> > + __u64 pad;
> > +};
> > +
> > #define SYNC_IOC_MAGIC '>'
> >
> > /**
> > @@ -95,4 +110,11 @@ 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()
>
> Does something here provide doc links to struct sync_set_deadline and
> to the "DOC: deadline hints"?
>
> > + */
> > +#define SYNC_IOC_SET_DEADLINE_IOW(SYNC_IOC_MAGIC, 5, struct
> > sync_set_deadline)
> > +
> > #endif /* _UAPI_LINUX_SYNC_H */
>
> With all those links added:
> Acked-by: Pekka Paalanen
>
>
> Thanks,
> pq
