Re: [PATCH v3 7/9] media: subdev: Support privacy led in v4l2_subdev_enable/disable_streams()

From: Laurent Pinchart
Date: Fri Apr 19 2024 - 06:22:30 EST


On Tue, Apr 16, 2024 at 01:34:22PM +0300, Tomi Valkeinen wrote:
> On 12/04/2024 21:20, Laurent Pinchart wrote:
> > Hi Tomi,
> >
> > Thank you for the patch.
> >
> > On Wed, Apr 10, 2024 at 03:35:54PM +0300, Tomi Valkeinen wrote:
> >> We support camera privacy leds with the .s_stream, in call_s_stream, but
> >
> > s/the .s_stream/the .s_stream() operation/
> >
> >> we don't have that support when the subdevice implements
> >> .enable/disable_streams.
> >>
> >> Add the support by enabling the led when the first stream for a
> >> subdevice is enabled, and disabling the led then the last stream is
> >> disabled.
> >
> > I wonder if that will always be the correct constraint for all devices,
> > but I suppose we can worry about it later.
> >
> >> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
> >> ---
> >> drivers/media/v4l2-core/v4l2-subdev.c | 9 +++++++++
> >> 1 file changed, 9 insertions(+)
> >>
> >> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> >> index 20b5a00cbeeb..f44aaa4e1fab 100644
> >> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> >> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> >> @@ -2150,6 +2150,7 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
> >> {
> >> struct device *dev = sd->entity.graph_obj.mdev->dev;
> >> struct v4l2_subdev_state *state;
> >> + bool already_streaming;
> >> u64 found_streams = 0;
> >> unsigned int i;
> >> int ret;
> >> @@ -2198,6 +2199,8 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
> >>
> >> dev_dbg(dev, "enable streams %u:%#llx\n", pad, streams_mask);
> >>
> >> + already_streaming = v4l2_subdev_is_streaming(sd);
> >> +
> >> /* Call the .enable_streams() operation. */
> >> ret = v4l2_subdev_call(sd, pad, enable_streams, state, pad,
> >> streams_mask);
> >> @@ -2216,6 +2219,9 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
> >> cfg->enabled = true;
> >> }
> >>
> >> + if (!already_streaming)
> >> + v4l2_subdev_enable_privacy_led(sd);
> >> +
> >> done:
> >> v4l2_subdev_unlock_state(state);
> >>
> >> @@ -2340,6 +2346,9 @@ int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad,
> >> }
> >>
> >> done:
> >> + if (!v4l2_subdev_is_streaming(sd))
> >
> > Wouldn't it be more efficient to check this while looping over the
> > stream configs in the loop just above ? Same for
> > v4l2_subdev_enable_streams().
>
> It would, but it would get a lot messier to manage with "media: subdev:
> Refactor v4l2_subdev_enable/disable_streams()", and we would also need
> to support the non-routing case.

True.

> This is usually a loop with a couple of iterations, and only called when
> enabling or enabling a subdevice, so I'm not really worried about the
> performance. If it's an issue, it would probably be better to also
> update the sd->enabled_pads when enabling/disabling a stream.

OK, I can live with that for now.

--
Regards,

Laurent Pinchart