Hi Sakari, On Fri, Oct 18, 2024 at 07:30:30PM +0000, Sakari Ailus wrote: > Hi Tommaso, > > Thanks for working on this. In real it's a Laurent's suggestion :) > > On Fri, Oct 18, 2024 at 07:11:03PM +0200, Tommaso Merciai wrote: > > Controls can be exposed to userspace via a v4l-subdevX device, and > > userspace has to be able to subscribe to control events so that it is > > notified when the control changes value. > > If a control handler is set for the subdev then set the HAS_EVENTS > > flag automatically into v4l2_subdev_init_finalize() and use > > v4l2_ctrl_subdev_subscribe_event() and v4l2_event_subdev_unsubscribe() > > as default if subdev don't have .(un)subscribe control operations. > > > > Signed-off-by: Tommaso Merciai <tomm.merciai@xxxxxxxxx> > > --- > > drivers/media/v4l2-core/v4l2-subdev.c | 22 ++++++++++++++++++++-- > > 1 file changed, 20 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c > > index 3a4ba08810d2..77ca829b9983 100644 > > --- a/drivers/media/v4l2-core/v4l2-subdev.c > > +++ b/drivers/media/v4l2-core/v4l2-subdev.c > > @@ -691,10 +691,25 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg, > > return v4l2_event_dequeue(vfh, arg, file->f_flags & O_NONBLOCK); > > > > case VIDIOC_SUBSCRIBE_EVENT: > > - return v4l2_subdev_call(sd, core, subscribe_event, vfh, arg); > > + if (v4l2_subdev_has_op(sd, core, subscribe_event)) > > + return v4l2_subdev_call(sd, core, subscribe_event, > > + vfh, arg); > > + > > + if ((sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS) && > > + vfh->ctrl_handler) > > + return v4l2_ctrl_subdev_subscribe_event(sd, vfh, arg); > > + > > + return -ENOIOCTLCMD; > > While this mostly does the same thing, I prefer the order of tests below. > Could you align event subscription with unsubscription? What about: case VIDIOC_SUBSCRIBE_EVENT: if (!(sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS)) return -ENOIOCTLCMD; if (v4l2_subdev_has_op(sd, core, subscribe_event)) return v4l2_subdev_call(sd, core, subscribe_event, vfh, arg); if (!vfh->ctrl_handler) return -ENOTTY; return v4l2_ctrl_subdev_subscribe_event(sd, vfh, arg); case VIDIOC_UNSUBSCRIBE_EVENT: if (!(sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS)) return -ENOIOCTLCMD; if (v4l2_subdev_has_op(sd, core, unsubscribe_event)) return v4l2_subdev_call(sd, core, unsubscribe_event, vfh, arg); return v4l2_event_subdev_unsubscribe(sd, vfh, arg); ? Thanks & Regards, Tommaso > > > > > case VIDIOC_UNSUBSCRIBE_EVENT: > > - return v4l2_subdev_call(sd, core, unsubscribe_event, vfh, arg); > > + if (!(sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS)) > > + return -ENOIOCTLCMD; > > + > > + if (v4l2_subdev_has_op(sd, core, unsubscribe_event)) > > + return v4l2_subdev_call(sd, core, unsubscribe_event, > > + vfh, arg); > > + > > + return v4l2_event_subdev_unsubscribe(sd, vfh, arg); > > > > #ifdef CONFIG_VIDEO_ADV_DEBUG > > case VIDIOC_DBG_G_REGISTER: > > @@ -1641,6 +1656,9 @@ int __v4l2_subdev_init_finalize(struct v4l2_subdev *sd, const char *name, > > } > > } > > > > + if (sd->ctrl_handler) > > + sd->flags |= V4L2_SUBDEV_FL_HAS_EVENTS; > > + > > state = __v4l2_subdev_state_alloc(sd, name, key); > > if (IS_ERR(state)) > > return PTR_ERR(state); > > -- > Kind regards, > > Sakari Ailus
