Re: [PATCH] drm/syncobj: Extend EXPORT_SYNC_FILE for timeline syncobjs

[Christian König]

Am 26.03.25 um 15:39 schrieb Rob Clark:
> From: Rob Clark <robdclark@xxxxxxxxxxxx>
>
> Add support for exporting a dma_fence fd for a specific point on a
> timeline.

Looks good on first glance. What's the userspace use case?

Regards,
Christian.

>
> Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/drm_syncobj.c | 8 ++++++--
>  include/uapi/drm/drm.h        | 2 ++
>  2 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
> index 4f2ab8a7b50f..eb7a2dd2e261 100644
> --- a/drivers/gpu/drm/drm_syncobj.c
> +++ b/drivers/gpu/drm/drm_syncobj.c
> @@ -762,7 +762,7 @@ static int drm_syncobj_import_sync_file_fence(struct drm_file *file_private,
>  }
>  
>  static int drm_syncobj_export_sync_file(struct drm_file *file_private,
> -					int handle, int *p_fd)
> +					int handle, u64 point, int *p_fd)
>  {
>  	int ret;
>  	struct dma_fence *fence;
> @@ -772,7 +772,7 @@ static int drm_syncobj_export_sync_file(struct drm_file *file_private,
>  	if (fd < 0)
>  		return fd;
>  
> -	ret = drm_syncobj_find_fence(file_private, handle, 0, 0, &fence);
> +	ret = drm_syncobj_find_fence(file_private, handle, point, 0, &fence);
>  	if (ret)
>  		goto err_put_fd;
>  
> @@ -882,8 +882,12 @@ drm_syncobj_handle_to_fd_ioctl(struct drm_device *dev, void *data,
>  
>  	if (args->flags & DRM_SYNCOBJ_HANDLE_TO_FD_FLAGS_EXPORT_SYNC_FILE)
>  		return drm_syncobj_export_sync_file(file_private, args->handle,
> +						    args->point,
>  						    &args->fd);
>  
> +	if (args->point)
> +		return -EINVAL;
> +
>  	return drm_syncobj_handle_to_fd(file_private, args->handle,
>  					&args->fd);
>  }
> diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
> index 7fba37b94401..c71a8f4439f2 100644
> --- a/include/uapi/drm/drm.h
> +++ b/include/uapi/drm/drm.h
> @@ -912,6 +912,8 @@ struct drm_syncobj_handle {
>  
>  	__s32 fd;
>  	__u32 pad;
> +
> +	__u64 point;
>  };
>  
>  struct drm_syncobj_transfer {