On Fri, 3 Sep 2021 11:47:59 -0700 Rob Clark <robdcl...@gmail.com> wrote:
> From: Rob Clark <robdcl...@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 <robdcl...@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.
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 */
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