Re: [PATCH v7 03/15] media: i2c: imx219: Report internal routes to userspace

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Moi,

On Thu, Apr 04, 2024 at 11:19:22AM +0300, Tomi Valkeinen wrote:
> Hi,
> 
> On 25/03/2024 00:08, Laurent Pinchart wrote:
> > Usage of internal pads creates a route internal to the subdev, and the
> > V4L2 camera sensor API requires such routes to be reported to userspace.
> > Create the route in the .init_state() operation.
> > 
> > Internal routing support requires stream support, so set the
> > V4L2_SUBDEV_FL_HAS_STREAMS flag and switch formats and selection
> 
> It's V4L2_SUBDEV_FL_STREAMS (not sure why, as the other flags have _HAS_).

Didn't you write the patch to add the flag? :-)

In any case, I think the flat is used for a very similar purpose than the
rest, I'd add "HAS_" here, too. I can write a patch.

> 
> > rectangles access from pads to streams. As the route is immutable,
> > there's no need to implement the .set_routing() operation, and we can
> > hardcode the sink and source stream IDs to 0.
> 
> This doesn't implement .enable/disable_streams(), but continues using
> .s_stream(). My understanding was that streams support requires
> .enable/disable_streams(), but obviously the framework doesn't require this
> at the moment.
> 
> I encountered this while working on improving the
> v4l2_subdev_enable/disable_streams(), and my code assumed that only
> implementing .s_stream() means no streams support.
> 
> So, how is it?
> 
> I would say that .s_stream() is legacy, and streams enabled subdevices
> should not implement (only) it. Streams enabled subdevices can use
> v4l2_subdev_s_stream_helper for .s_stream, in addition to implementing
> .enable/disable_streams().

I agree, if the driver supports streams, then it needs to implement the
appropriate callbacks (i.e. not s_stream).

> 
>  Tomi
> 
> > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
> > ---
> > Changes since v6:
> > 
> > - Drop change to get format API in imx219_set_ctrl()
> > - Fix function name in commit message
> > - Set V4L2_SUBDEV_ROUTE_FL_IMMUTABLE flag on route
> > ---
> >   drivers/media/i2c/imx219.c | 24 +++++++++++++++++++++++-
> >   1 file changed, 23 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/media/i2c/imx219.c b/drivers/media/i2c/imx219.c
> > index 817bf192e4d9..6602250834be 100644
> > --- a/drivers/media/i2c/imx219.c
> > +++ b/drivers/media/i2c/imx219.c
> > @@ -993,15 +993,36 @@ static int imx219_get_selection(struct v4l2_subdev *sd,
> >   static int imx219_init_state(struct v4l2_subdev *sd,
> >   			     struct v4l2_subdev_state *state)
> >   {
> > +	struct v4l2_subdev_route routes[1] = {
> > +		{
> > +			.sink_pad = IMX219_PAD_IMAGE,
> > +			.sink_stream = 0,
> > +			.source_pad = IMX219_PAD_SOURCE,
> > +			.source_stream = 0,
> > +			.flags = V4L2_SUBDEV_ROUTE_FL_ACTIVE |
> > +				 V4L2_SUBDEV_ROUTE_FL_IMMUTABLE,
> > +		},
> > +	};
> > +	struct v4l2_subdev_krouting routing = {
> > +		.len_routes = ARRAY_SIZE(routes),
> > +		.num_routes = ARRAY_SIZE(routes),
> > +		.routes = routes,
> > +	};
> >   	struct v4l2_subdev_format fmt = {
> >   		.which = V4L2_SUBDEV_FORMAT_TRY,
> >   		.pad = IMX219_PAD_SOURCE,
> > +		.stream = 0,
> >   		.format = {
> >   			.code = MEDIA_BUS_FMT_SRGGB10_1X10,
> >   			.width = supported_modes[0].width,
> >   			.height = supported_modes[0].height,
> >   		},
> >   	};
> > +	int ret;
> > +
> > +	ret = v4l2_subdev_set_routing(sd, state, &routing);
> > +	if (ret)
> > +		return ret;
> >   	imx219_set_pad_format(sd, state, &fmt);
> > @@ -1260,7 +1281,8 @@ static int imx219_probe(struct i2c_client *client)
> >   	/* Initialize subdev */
> >   	imx219->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE |
> > -			    V4L2_SUBDEV_FL_HAS_EVENTS;
> > +			    V4L2_SUBDEV_FL_HAS_EVENTS |
> > +			    V4L2_SUBDEV_FL_STREAMS;
> >   	imx219->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
> >   	/*
> 

-- 
Terveisin,

Sakari Ailus