Hi Sakari,
On Fri, Aug 18, 2023 at 04:18:41PM +0000, Sakari Ailus wrote:
> On Fri, Aug 18, 2023 at 06:55:18PM +0300, Laurent Pinchart wrote:
> > Routing support, through the subdev .set_routing() operation, requires
> > the subdev to support streams. This is however not clearly documented
> > anywhere. Fix it by expanding the operation's documentation to indicate
> > that subdevs must set the V4L2_SUBDEV_FL_STREAMS flag.
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> > ---
> > include/media/v4l2-subdev.h | 5 +++--
> > 1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
> > index b325df0d54d6..0b04ed1994b6 100644
> > --- a/include/media/v4l2-subdev.h
> > +++ b/include/media/v4l2-subdev.h
> > @@ -822,8 +822,9 @@ struct v4l2_subdev_state {
> > * operation shall fail if the pad index it has been called on
> > * is not valid or in case of unrecoverable failures.
> > *
> > - * @set_routing: enable or disable data connection routes described in the
> > - * subdevice routing table.
> > + * @set_routing: Enable or disable data connection routes described in the
> > + * subdevice routing table. Subdevs that implement this operation
> > + * must set the V4L2_SUBDEV_FL_STREAMS flag.
>
> Could we set the flag in the core when this op exists for a sub-device?
That won't work in all cases, as a driver could expose immutable routes
by creating them in the .init_cfg() function, without implementing
.set_routing().
Another option would be to check if the drivers has created routes after
the .init_cfg() called (indirectly) from v4l2_subdev_init_finalize(). It
may be a bit fragile though.
> We could do similarly for events when the sub-device has a control handler.
A subdev could generate non-control events too. In most cases I suppose
it would still create a control handler, but I don't think we should
require that.
> The device node should probably exist in almost all cases, but I'm not sure
> right now whether there is a reasonable test for it.
--
Regards,
Laurent Pinchart
