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

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

Moi,

On Thu, Jun 26, 2025 at 06:17:13PM +0300, Tomi Valkeinen wrote:
> Hi,
> 
> On 19/06/2025 11:15, Sakari Ailus wrote:
> > Streams are stored in sink-source pairs in sub-device state. When a stream
> > was marked enabled (or disabled), only the state of one end of the stream
> > was modified, leaving the stream in an incoherent state. Mark both ends of
> > the stream enabled (or disabled).
> > 
> > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > ---
> >  drivers/media/v4l2-core/v4l2-subdev.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> > index 60b8febd3339..5afdd9d548b5 100644
> > --- a/drivers/media/v4l2-core/v4l2-subdev.c
> > +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> > @@ -2254,9 +2254,11 @@ static void v4l2_subdev_set_streams_enabled(struct v4l2_subdev *sd,
> >  	for (unsigned int i = 0; i < state->stream_configs.num_configs; ++i) {
> >  		struct v4l2_subdev_stream_config *cfg =
> >  			&state->stream_configs.configs[i];
> > +		struct v4l2_subdev_stream_config *cfg2 =
> > +			&state->stream_configs.configs[i ^ 1U];
> 
> I don't think this is correct. There's no specific rule that the stream
> configs would be in a particular order. Or that there even are a pair.
> 
> You should look for the other end of the stream from the routing table.

Currently the code managing the streams stores them in this array in pairs,
the sink followed by the source for each route. As noted in the commit
message, this patch also fixes a bug.

I can change the patch to use routes to find the other end, but over time
we might want to use a different data structure to store this information
(a linked list perhaps). The number of routes and stream configurations is
presumably fairly small in most cases so right now I presume there's no
noteworthy effect on performance.

-- 
Terveisin,

Sakari Ailus