Hi Hans,
A code excerpt is better than a long story, so here it is (from
drivers/media/video/v4l2-device.c).
> int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
> struct v4l2_subdev *sd)
> {
> int err;
>
> /* Check for valid input */
> if (v4l2_dev == NULL || sd == NULL || !sd->name[0])
> return -EINVAL;
> /* Warn if we apparently re-register a subdev */
> WARN_ON(sd->v4l2_dev != NULL);
> if (!try_module_get(sd->owner))
> return -ENODEV;
> /* This just returns 0 if either of the two args is NULL */
> err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd-
>ctrl_handler);
> if (err)
A call to module_put() is needed here. That one is easy to fix.
> return err;
> sd->v4l2_dev = v4l2_dev;
> spin_lock(&v4l2_dev->lock);
> list_add_tail(&sd->list, &v4l2_dev->subdevs);
> spin_unlock(&v4l2_dev->lock);
The subdev device node patches add a device node registration call here, and
the call might fail. How do I cleanup the v4l2_ctrl_add_handler() call ? There
doesn't seem to be any v4l2_ctrl_remove_handler() function. The same problem
exists in v4l2_device_unregister_subdev(), you're not cleaning up the control
framework there.
> return 0;
> }
> EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
--
Regards,
Laurent Pinchart
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