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

[Tomi Valkeinen]

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.

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.

 Tomi