Hi Laurent, Thanks for the review. On Tue, Sep 26, 2023 at 12:34:50AM +0300, Laurent Pinchart wrote: > On Tue, Sep 26, 2023 at 12:01:02AM +0300, Laurent Pinchart wrote: > > Hi Sakari, > > > > Thank you for the patch. > > > > On Fri, Sep 22, 2023 at 05:22:35PM +0300, Sakari Ailus wrote: > > > The len_routes field is used to tell the size of the routes array in > > > struct v4l2_subdev_routing. This way the number of routes returned from > > > S_ROUTING IOCTL may be larger than the number of routes provided, in case > > > there are more routes returned by the driver. > > > > > > Note that this changes the (now-disabled) UAPI, users must be updated. > > > > This cause a regression in all upstream drivers that call > > v4l2_subdev_set_routing(). You need to patch the following files: > > > > drivers/media/i2c/ds90ub913.c > > drivers/media/i2c/ds90ub953.c > > drivers/media/i2c/ds90ub960.c > > drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c > > > > It's a bit error-prone though. Consider the following change: > > > > diff --git a/drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c b/drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c > > index 792f031e032a..c1c9e7018f24 100644 > > --- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c > > +++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-crossbar.c > > @@ -201,6 +201,7 @@ static int mxc_isi_crossbar_init_cfg(struct v4l2_subdev *sd, > > route->flags = V4L2_SUBDEV_ROUTE_FL_ACTIVE; > > } > > > > + routing.len_routes = xbar->num_sources; > > routing.num_routes = xbar->num_sources; > > routing.routes = routes; > > > > It's easy to forget to set len_routes :-S I wonder if we could do > > better. > > Actually, this isn't needed. My problem was caused by a bug in patch > 21/23. > > Still, not initializing len_routes in drivers feels wrong. len_routes signifies the number of routes that can fit to the user-allocated routes array. Drivers do need to ensure they don't write more routes there, as the kernel allocates as much memory for the in-kernel array. -- Kind regards, Sakari Ailus
