Re: [PATCH v1 10/19] uvcvideo: Support UVC 1.5 runtime control property.

Laurent Pinchart
2013-11-10T22:51:26Z

Hi Pawel,

Thank you for the patch.

On Friday 30 August 2013 11:17:09 Pawel Osciak wrote:
> UVC 1.5 introduces the concept of runtime controls, which can be set during
> streaming. Non-runtime controls can only be changed while device is idle.
>
> Signed-off-by: Pawel Osciak <posciak@chromium.org>
> ---
> drivers/media/usb/uvc/uvc_ctrl.c | 45 ++++++++++++++++++++++++++++++-------
> drivers/media/usb/uvc/uvc_v4l2.c | 18 ++++++++++------
> drivers/media/usb/uvc/uvcvideo.h | 12 +++++++----
> 3 files changed, 57 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c
> b/drivers/media/usb/uvc/uvc_ctrl.c index d735c88..b0a19b9 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -1076,8 +1076,19 @@ void __uvc_ctrl_unlock(struct uvc_video_chain *chain)
> mutex_unlock(&chain->pipeline->ctrl_mutex);
> }
>
> +static int uvc_check_ctrl_runtime(struct uvc_control *ctrl, bool streaming)
> +{
> + if (streaming && !ctrl->in_runtime) {
> + uvc_trace(UVC_TRACE_CONTROL,
> + "Control disabled while streaming\n");
> + return -EBUSY;
> + }
> +
> + return 0;
> +}
> +
> int uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
> - struct v4l2_queryctrl *v4l2_ctrl)
> + struct v4l2_queryctrl *v4l2_ctrl, bool streaming)
> {
> struct uvc_control *ctrl;
> struct uvc_control_mapping *mapping;
> @@ -1093,6 +1104,10 @@ int uvc_query_v4l2_ctrl(struct uvc_video_chain
> *chain, goto done;
> }
>
> + ret = uvc_check_ctrl_runtime(ctrl, streaming);
> + if (ret < 0)
> + goto done;
> +

Do we really need to disallow querying controls during streaming ? Shouldn't
we cache the runtime controls at init time instead ?

> ret = __uvc_query_v4l2_ctrl(chain, ctrl, mapping, v4l2_ctrl);
> done:
> __uvc_ctrl_unlock(chain);
> @@ -1109,7 +1124,7 @@ done:
> * manually.
> */
> int uvc_query_v4l2_menu(struct uvc_video_chain *chain,
> - struct v4l2_querymenu *query_menu)
> + struct v4l2_querymenu *query_menu, bool streaming)
> {
> struct uvc_menu_info *menu_info;
> struct uvc_control_mapping *mapping;
> @@ -1132,6 +1147,10 @@ int uvc_query_v4l2_menu(struct uvc_video_chain
> *chain, goto done;
> }
>
> + ret = uvc_check_ctrl_runtime(ctrl, streaming);
> + if (ret < 0)
> + goto done;
> +

Same here.

> if (query_menu->index >= mapping->menu_count) {
> ret = -EINVAL;
> goto done;
> @@ -1436,21 +1455,26 @@ done:
> return ret;
> }
>
> -int uvc_ctrl_get(struct uvc_video_chain *chain,
> - struct v4l2_ext_control *xctrl)
> +int uvc_ctrl_get(struct uvc_video_chain *chain, struct v4l2_ext_control
> *xctrl,
> + bool streaming)
> {
> struct uvc_control *ctrl;
> struct uvc_control_mapping *mapping;
> + int ret;
>
> ctrl = uvc_find_control(chain, xctrl->id, &mapping);
> if (ctrl == NULL)
> return -EINVAL;
>
> + ret = uvc_check_ctrl_runtime(ctrl, streaming);
> + if (ret < 0)
> + return ret;
> +

Even for the get operation, would it be possible to use the cached value ? Can
a runtime control be also an auto-update or asynchronous control ?

> return __uvc_ctrl_get(chain, ctrl, mapping, &xctrl->value);
> }
>
> -int uvc_ctrl_set(struct uvc_video_chain *chain,
> - struct v4l2_ext_control *xctrl)
> +int uvc_ctrl_set(struct uvc_video_chain *chain, struct v4l2_ext_control
> *xctrl,
> + bool streaming)
> {
> struct uvc_control *ctrl;
> struct uvc_control_mapping *mapping;
> @@ -1466,6 +1490,10 @@ int uvc_ctrl_set(struct uvc_video_chain *chain,
> if (!(ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR))
> return -EACCES;
>
> + ret = uvc_check_ctrl_runtime(ctrl, streaming);
> + if (ret < 0)
> + return ret;
> +
> /* Clamp out of range values. */
> switch (mapping->v4l2_type) {
> case V4L2_CTRL_TYPE_INTEGER:
> @@ -1885,8 +1913,9 @@ static int uvc_ctrl_add_info(struct uvc_device *dev,
> struct uvc_control *ctrl, ctrl->initialized = 1;
>
> uvc_trace(UVC_TRACE_CONTROL, "Added control %pUl/%u to device %s "
> - "entity %u\n", ctrl->info.entity, ctrl->info.selector,
> - dev->udev->devpath, ctrl->entity->id);
> + "entity %u, init/runtime %d/%d\n", ctrl->info.entity,

%u/%u ?

> + ctrl->info.selector, dev->udev->devpath, ctrl->entity->id,
> + ctrl->on_init, ctrl->in_runtime);
>
> done:
> if (ret < 0)
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c
> b/drivers/media/usb/uvc/uvc_v4l2.c index a899159..decd65f 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -597,7 +597,8 @@ static long uvc_v4l2_do_ioctl(struct file *file,
> unsigned int cmd, void *arg)
>
> /* Get, Set & Query control */
> case VIDIOC_QUERYCTRL:
> - return uvc_query_v4l2_ctrl(chain, arg);
> + return uvc_query_v4l2_ctrl(chain, arg,
> + uvc_is_stream_streaming(stream));

Can't this (and all the similar constructs below) race with the
VIDIOC_STREAMON/OFF ioctls ?

> case VIDIOC_G_CTRL:
> {
> @@ -611,7 +612,8 @@ static long uvc_v4l2_do_ioctl(struct file *file,
> unsigned int cmd, void *arg) if (ret < 0)
> return ret;
>
> - ret = uvc_ctrl_get(chain, &xctrl);
> + ret = uvc_ctrl_get(chain, &xctrl,
> + uvc_is_stream_streaming(stream));
> uvc_ctrl_rollback(handle);
> if (ret >= 0)
> ctrl->value = xctrl.value;
> @@ -635,7 +637,8 @@ static long uvc_v4l2_do_ioctl(struct file *file,
> unsigned int cmd, void *arg) if (ret < 0)
> return ret;
>
> - ret = uvc_ctrl_set(chain, &xctrl);
> + ret = uvc_ctrl_set(chain, &xctrl,
> + uvc_is_stream_streaming(stream));
> if (ret < 0) {
> uvc_ctrl_rollback(handle);
> return ret;
> @@ -647,7 +650,8 @@ static long uvc_v4l2_do_ioctl(struct file *file,
> unsigned int cmd, void *arg) }
>
> case VIDIOC_QUERYMENU:
> - return uvc_query_v4l2_menu(chain, arg);
> + return uvc_query_v4l2_menu(chain, arg,
> + uvc_is_stream_streaming(stream));
>
> case VIDIOC_G_EXT_CTRLS:
> {
> @@ -660,7 +664,8 @@ static long uvc_v4l2_do_ioctl(struct file *file,
> unsigned int cmd, void *arg) return ret;
>
> for (i = 0; i < ctrls->count; ++ctrl, ++i) {
> - ret = uvc_ctrl_get(chain, ctrl);
> + ret = uvc_ctrl_get(chain, ctrl,
> + uvc_is_stream_streaming(stream));
> if (ret < 0) {
> uvc_ctrl_rollback(handle);
> ctrls->error_idx = i;
> @@ -688,7 +693,8 @@ static long uvc_v4l2_do_ioctl(struct file *file,
> unsigned int cmd, void *arg) return ret;
>
> for (i = 0; i < ctrls->count; ++ctrl, ++i) {
> - ret = uvc_ctrl_set(chain, ctrl);
> + ret = uvc_ctrl_set(chain, ctrl,
> + uvc_is_stream_streaming(stream));
> if (ret < 0) {
> uvc_ctrl_rollback(handle);
> ctrls->error_idx = cmd == VIDIOC_S_EXT_CTRLS
> diff --git a/drivers/media/usb/uvc/uvcvideo.h
> b/drivers/media/usb/uvc/uvcvideo.h index 88f5e38..46ffd92 100644
> --- a/drivers/media/usb/uvc/uvcvideo.h
> +++ b/drivers/media/usb/uvc/uvcvideo.h
> @@ -694,6 +694,10 @@ extern int uvc_query_ctrl(struct uvc_device *dev, __u8
> query, __u8 unit, void uvc_video_clock_update(struct uvc_streaming *stream,
> struct v4l2_buffer *v4l2_buf,
> struct uvc_buffer *buf);
> +static inline bool uvc_is_stream_streaming(struct uvc_streaming *stream)
> +{
> + return vb2_is_streaming(&stream->queue.queue);
> +}
>
> /* Status */
> extern int uvc_status_init(struct uvc_device *dev);
> @@ -705,9 +709,9 @@ extern void uvc_status_stop(struct uvc_device *dev);
> extern const struct v4l2_subscribed_event_ops uvc_ctrl_sub_ev_ops;
>
> extern int uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
> - struct v4l2_queryctrl *v4l2_ctrl);
> + struct v4l2_queryctrl *v4l2_ctrl, bool streaming);
> extern int uvc_query_v4l2_menu(struct uvc_video_chain *chain,
> - struct v4l2_querymenu *query_menu);
> + struct v4l2_querymenu *query_menu, bool streaming);
>
> extern int uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
> const struct uvc_control_mapping *mapping);
> @@ -731,9 +735,9 @@ static inline int uvc_ctrl_rollback(struct uvc_fh
> *handle) }
>
> extern int uvc_ctrl_get(struct uvc_video_chain *chain,
> - struct v4l2_ext_control *xctrl);
> + struct v4l2_ext_control *xctrl, bool streaming);
> extern int uvc_ctrl_set(struct uvc_video_chain *chain,
> - struct v4l2_ext_control *xctrl);
> + struct v4l2_ext_control *xctrl, bool streaming);
>
> extern int uvc_xu_ctrl_query(struct uvc_video_chain *chain,
> struct uvc_xu_control_query *xqry);
--
Regards,

Laurent Pinchart