Re: [PATCH v4 20/29] media: uapi: Bump the STREAMS bit a little

Laurent Pinchart
2026-04-16T14:31:16Z

On Fri, Apr 10, 2026 at 11:31:06AM +0200, Jacopo Mondi wrote:
> On Wed, Apr 08, 2026 at 06:39:29PM +0300, Sakari Ailus wrote:
> > Bump the V4L2_SUBDEV_CAP_STREAMS by one bit up, order to avoid confusing
> > libcamera with streams that has moved forward from the original libcamera
> > implementation. The bit can presumably be taken into use but only after
> > the other free bits.
> >
> > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
>
> Thanks!
> Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
>
> > ---
> > include/uapi/linux/v4l2-subdev.h | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/uapi/linux/v4l2-subdev.h b/include/uapi/linux/v4l2-subdev.h
> > index 2347e266cf75..6160c3e21436 100644
> > --- a/include/uapi/linux/v4l2-subdev.h
> > +++ b/include/uapi/linux/v4l2-subdev.h
> > @@ -196,8 +196,11 @@ struct v4l2_subdev_capability {
> > /* The v4l2 sub-device video device node is registered in read-only mode. */
> > #define V4L2_SUBDEV_CAP_RO_SUBDEV 0x00000001
> >
> > +/* Reserved, old STREAMS bit libcamera used before API stabilisation. */
> > +/* #define V4L2_SUBDEV_CAP_STREAMS_PRELIMINARY 0x00000002 */
>
> This should make sure libcamera versions which support the new flag
> won't match agains older kernel which use the old value!

Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

Could we delay merging this patch until we work on implementing the new
behaviour in libcamera ?

> > +
> > /* The v4l2 sub-device supports routing and multiplexed streams. */
> > -#define V4L2_SUBDEV_CAP_STREAMS 0x00000002
> > +#define V4L2_SUBDEV_CAP_STREAMS 0x00000004
> >
> > /*
> > * Is the route active? An active route will start when streaming is enabled

--
Regards,

Laurent Pinchart