Hi Yunke Thank you very much for the patchset :) On Wed, 11 Jan 2023 at 09:52, Yunke Cao <yunkec@xxxxxxxxxxxx> wrote: > > privacy_gpio in uvc were added as V4L2_CID_PRIVACY in uvc video node in > https://lore.kernel.org/all/20201223133528.55014-1-ribalda@xxxxxxxxxxxx/ > > Userspace applications often require to constantly poll privacy control. > Currently, polling privacy control requires keeping the video node open, > which prevents the camera from autosuspending. > > This patchset adds a separate v4l2 subdevice. Userspace access the gpio > via V4L2_CID_PRIVACY in the new subdevice. Applications can poll the > privacy control status without opening the video node and activate the > camera. > > The non-gpio V4L2_CID_PRIVACY in uvc is not affected. Since this is a RFC, lets focus on the idea and not on the code itself. - I am missing a reference to the subdevice from the media device. How will a user figure out that /dev/v4l-subdev0 is the privacy gpio of /dev/media0 and not /dev/media1?. Thake a look to the "ancillary links" - We have already exposed the control as part of the main video device, that means that we need to keep that API. The control on /dev/v4l-subdev0 should "mirror" the control on /dev/video0 - There is no need to v4l2_ctrl_fill_event(), if you modify the control with a set controll function, the media controller should take care of everything @Sakari Ailus @Hans Verkuil : Assuming a correct implementation, how would you feel about exposing a privacy gpio as a subdevice? Thanks!!! > > Suggested-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx> > Signed-off-by: Yunke Cao <yunkec@xxxxxxxxxxxx> > --- > Yunke Cao (3): > media: v4l2-ctrls: Expose v4l2_ctrl_fill_event() > media: uvcvideo: remove entity privacy control in the uvc video node > media: uvcvideo: reimplement privacy GPIO as a separate subdevice > > drivers/media/usb/uvc/uvc_ctrl.c | 17 ------- > drivers/media/usb/uvc/uvc_driver.c | 44 ++---------------- > drivers/media/usb/uvc/uvc_entity.c | 76 +++++++++++++++++++++++++++++++ > drivers/media/usb/uvc/uvcvideo.h | 19 +++++--- > drivers/media/v4l2-core/v4l2-ctrls-core.c | 9 ++-- > include/media/v4l2-ctrls.h | 12 +++++ > 6 files changed, 111 insertions(+), 66 deletions(-) > --- > base-commit: 7dd4b804e08041ff56c88bdd8da742d14b17ed25 > change-id: 20230111-uvc_privacy_subdev-1e7a167e86eb > > Best regards, > -- > Yunke Cao <yunkec@xxxxxxxxxxxx> -- Ricardo Ribalda
