On Thu, 2021-01-14 at 18:11 +0200, Sakari Ailus wrote:
> On Thu, Jan 14, 2021 at 11:46:11AM -0300, Ezequiel Garcia wrote:
> > On Thu, 2021-01-14 at 15:47 +0200, Sakari Ailus wrote:
> > > Hi Laurent, Ezequiel,
> > >
> > > On Thu, Jan 14, 2021 at 03:59:10AM +0200, Laurent Pinchart wrote:
> > > > > diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c
> > > > > index 68da1eed753d..235dcf0c4122 100644
> > > > > --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c
> > > > > +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c
> > > > > @@ -252,6 +252,7 @@ static int rkisp1_subdev_notifier(struct rkisp1_device *rkisp1)
> > > > > .bus_type = V4L2_MBUS_CSI2_DPHY
> > > > > };
> > > > > struct rkisp1_sensor_async *rk_asd = NULL;
> > > > > + struct v4l2_async_subdev *asd;
> > > > > struct fwnode_handle *ep;
> > > > >
> > > > > ep = fwnode_graph_get_endpoint_by_id(dev_fwnode(rkisp1->dev),
> > > > > @@ -264,21 +265,16 @@ static int rkisp1_subdev_notifier(struct rkisp1_device *rkisp1)
> > > > > if (ret)
> > > > > goto err_parse;
> > > > >
> > > > > - rk_asd = kzalloc(sizeof(*rk_asd), GFP_KERNEL);
> > > > > - if (!rk_asd) {
> > > > > - ret = -ENOMEM;
> > > > > + asd = v4l2_async_notifier_add_fwnode_remote_subdev(ntf, ep,
> > > > > + sizeof(*rk_asd));
> > > > > + if (IS_ERR(asd))
> > >
> > > The problem with registering the sub-device already here is that the driver
> > > can proceed to use the information in the async sub-device object which is
> > > initialised below.
> > >
> >
> > Note that this interface is not really registering sub-devices.
>
> Not directly, but this will happen as a by-product of registering the async
> sub-device and other functions that will be called. All this takes place
> synchronously, meaming that by the time this function returns, the
> character devices that are the user space interface have already been
> created.
>
That's not the case, as I've explained before, v4l2_async_notifier_add_fwnode_remote_subdev
is _not_ about registering any actual v4l2 subdevice/char device.
It's just about adding the v4l2 async subdevice descriptor
to a given (unregistered) notifier.
Thanks,
Ezequiel
