Hi Ricardo,
Thank you for the patch.
On Thu, Feb 06, 2025 at 07:47:03PM +0000, Ricardo Ribalda wrote:
> Now we call uvc_status_get/put from the device open/close. This low
> level of granularity might leave the camera powered on in situations
> where it is not needed.
>
> Increase the granularity by increasing and decreasing the Power
> Management counter per ioctl. There are two special cases where the
> power management outlives the ioctl: async controls and streamon. Handle
> those cases as well.
>
> In a future patch, we will remove the uvc_status_get/put from open/close.
>
> Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
> ---
> drivers/media/usb/uvc/uvc_ctrl.c | 13 +++++++++++--
> drivers/media/usb/uvc/uvc_v4l2.c | 26 +++++++++++++++++++++++---
> 2 files changed, 34 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> index 4e58476d305e..97c1141a45b3 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -1594,12 +1594,15 @@ static void uvc_ctrl_set_handle(struct uvc_fh *handle, struct uvc_control *ctrl,
>
> if (ctrl->handle) {
> WARN_ON(!ctrl->handle->pending_async_ctrls);
> - if (ctrl->handle->pending_async_ctrls)
> + if (ctrl->handle->pending_async_ctrls) {
> ctrl->handle->pending_async_ctrls--;
> + uvc_status_put(handle->chain->dev);
That's not the right API. uvc_status_* is about the status endpoint, not
power management in general.
> + }
> }
>
> ctrl->handle = new_handle;
> handle->pending_async_ctrls++;
> + uvc_status_get(handle->chain->dev);
> return;
> }
>
> @@ -1611,6 +1614,7 @@ static void uvc_ctrl_set_handle(struct uvc_fh *handle, struct uvc_control *ctrl,
> if (WARN_ON(!handle->pending_async_ctrls))
> return;
> handle->pending_async_ctrls--;
> + uvc_status_put(handle->chain->dev);
> }
>
> void uvc_ctrl_status_event(struct uvc_video_chain *chain,
> @@ -2815,6 +2819,7 @@ int uvc_ctrl_init_device(struct uvc_device *dev)
> void uvc_ctrl_cleanup_fh(struct uvc_fh *handle)
> {
> struct uvc_entity *entity;
> + int i;
>
> guard(mutex)(&handle->chain->ctrl_mutex);
>
> @@ -2829,7 +2834,11 @@ void uvc_ctrl_cleanup_fh(struct uvc_fh *handle)
> }
> }
>
> - WARN_ON(handle->pending_async_ctrls);
> + if (!WARN_ON(handle->pending_async_ctrls))
> + return;
> +
> + for (i = 0; i < handle->pending_async_ctrls; i++)
> + uvc_status_put(handle->stream->dev);
> }
>
> /*
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
> index 5d4e967938af..63d1d06d3ff6 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -670,6 +670,9 @@ static int uvc_v4l2_release(struct file *file)
> if (uvc_has_privileges(handle))
> uvc_queue_release(&stream->queue);
>
> + if (handle->is_streaming)
> + uvc_status_put(stream->dev);
> +
> /* Release the file handle. */
> uvc_dismiss_privileges(handle);
> v4l2_fh_del(&handle->vfh);
> @@ -832,8 +835,10 @@ static int uvc_ioctl_streamon(struct file *file, void *fh,
> return 0;
>
> ret = uvc_queue_streamon(&stream->queue, type);
> - if (!ret)
> + if (!ret) {
> handle->is_streaming = true;
> + uvc_status_get(stream->dev);
> + }
>
> return ret;
>
> @@ -851,7 +856,10 @@ static int uvc_ioctl_streamoff(struct file *file, void *fh,
> guard(mutex)(&stream->mutex);
>
> uvc_queue_streamoff(&stream->queue, type);
> - handle->is_streaming = false;
> + if (handle->is_streaming) {
> + handle->is_streaming = false;
> + uvc_status_put(stream->dev);
> + }
>
> return 0;
> }
> @@ -1388,6 +1396,8 @@ static long uvc_v4l2_compat_ioctl32(struct file *file,
> void __user *up = compat_ptr(arg);
> long ret;
>
> + guard(uvc_status)(handle->stream->dev);
> +
> switch (cmd) {
> case UVCIOC_CTRL_MAP32:
> ret = uvc_v4l2_get_xu_mapping(&karg.xmap, up);
> @@ -1422,6 +1432,16 @@ static long uvc_v4l2_compat_ioctl32(struct file *file,
> }
> #endif
>
> +static long uvc_v4l2_video_ioctl2(struct file *file,
> + unsigned int cmd, unsigned long arg)
> +{
> + struct uvc_fh *handle = file->private_data;
> +
> + guard(uvc_status)(handle->stream->dev);
> +
> + return video_ioctl2(file, cmd, arg);
> +}
> +
> static ssize_t uvc_v4l2_read(struct file *file, char __user *data,
> size_t count, loff_t *ppos)
> {
> @@ -1507,7 +1527,7 @@ const struct v4l2_file_operations uvc_fops = {
> .owner = THIS_MODULE,
> .open = uvc_v4l2_open,
> .release = uvc_v4l2_release,
> - .unlocked_ioctl = video_ioctl2,
> + .unlocked_ioctl = uvc_v4l2_video_ioctl2,
> #ifdef CONFIG_COMPAT
> .compat_ioctl32 = uvc_v4l2_compat_ioctl32,
> #endif
--
Regards,
Laurent Pinchart
