Re: [PATCH 06/13] media: v4l2-subdev: Mark both streams of a route enabled

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Thu, Jun 26, 2025 at 06:22:53PM +0300, Tomi Valkeinen wrote:
> On 19/06/2025 21:34, Sakari Ailus wrote:
> > On Thu, Jun 19, 2025 at 07:56:04PM +0300, Laurent Pinchart wrote:
> >> On Thu, Jun 19, 2025 at 11:15:39AM +0300, Sakari Ailus wrote:
> >>> Streams are stored in sink-source pairs in sub-device state.
> >>
> >> Is it really this simple ? Don't we support for instance stream merging
> >> where two streams on possibly different sink pads are routed to a single
> >> stream on a source pad ?
> > 
> > As far as I'm concerned, yes. Each route has a sink and a source pad, you
> > may have multiple routes from a pad or to a pad, but these are all separate
> > routes. The UAPI as well as v4l2-subdev.c is aligned with this and I
> > wouldn't expect it to be otherwise.
> 
> But with stream merging/splitting we'll have one stream config on one
> pad, and two stream configs on the other. And thus two routes from that
> one config.

With the current code, we will have duplicated stream config entries for
the same stream in that case. Only the first one will be seen by the
v4l2_subdev_state_get_format() function, but both will exist.

> That said, if I recall right, I don't think merging/splitting has ever
> been really explored...

-- 
Regards,

Laurent Pinchart