[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20241021073034.GC14328@pendragon.ideasonboard.com>
Date: Mon, 21 Oct 2024 10:30:34 +0300
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Tommaso Merciai <tomm.merciai@...il.com>
Cc: sakari.ailus@...ux.intel.com,
Mauro Carvalho Chehab <mchehab@...nel.org>,
Hans Verkuil <hverkuil@...all.nl>,
Tomi Valkeinen <tomi.valkeinen@...asonboard.com>,
Paweł Anikiel <panikiel@...gle.com>,
linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] media: v4l2-subdev: Refactor events
On Mon, Oct 21, 2024 at 08:35:53AM +0200, Tommaso Merciai wrote:
> Hi Laurent,
> Thanks for your review.
>
> On Sun, Oct 20, 2024 at 07:43:54PM +0300, Laurent Pinchart wrote:
> > Hi Tommaso,
> >
> > Thank you for the patch.
> >
> > On Sun, Oct 20, 2024 at 06:35:32PM +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.
> >
> > I would add here
> >
> > This simplifies subdev drivers by avoiding the need to set the
> > V4L2_SUBDEV_FL_HAS_EVENTS flag and plug the event handlers, and ensures
> > consistency of the API exposed to userspace.
> >
> > And you can also add
> >
> > Suggested-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
> >
> > > Signed-off-by: Tommaso Merciai <tomm.merciai@...il.com>
> >
> > Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
>
> Oks, Thanks again.
>
> > Now, can we simplify sensor drivers to drop the event handlers and the
> > flag ? :-)
>
> Yep, plan is add all to support v4l2_subdev_init_finalize()
> Removing:
>
> .subscribe_event = v4l2_ctrl_subdev_subscribe_event,
> .unsubscribe_event = v4l2_event_subdev_unsubscribe,
>
> if are used. And ofc V4L2_SUBDEV_FL_HAS_EVENTS.
What I meant is looking at the I2C sensor drivers that currently
- call v4l2_subdev_init_finalize()
- set V4L2_SUBDEV_FL_HAS_EVENTS
- set the .subscribe_event() and .unsubscribe_event() handlers
and dropping the flag and handlers from them. Is that what you plan to
work on ?
> Meanwhile I think I will send v3 with your
> suggestions. :)
>
> > > ---
> > > Changes since v1:
> > > - Aligned event subscription with unsubscription as suggested by LPinchart,
> > > SAilus
> > >
> > > 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..fad8fa1f63e8 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;
> > >
> > > case VIDIOC_UNSUBSCRIBE_EVENT:
> > > - return v4l2_subdev_call(sd, core, unsubscribe_event, vfh, arg);
> > > + if (v4l2_subdev_has_op(sd, core, unsubscribe_event))
> > > + return v4l2_subdev_call(sd, core, unsubscribe_event,
> > > + vfh, arg);
> > > +
> > > + if (sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS)
> > > + return v4l2_event_subdev_unsubscribe(sd, vfh, arg);
> > > +
> > > + return -ENOIOCTLCMD;
> > >
> > > #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);
--
Regards,
Laurent Pinchart
Powered by blists - more mailing lists