On Wed, Jul 22, 2020 at 11:46:27AM +0200, Bastien Nocera wrote:
> When a new device with a specialised device driver is plugged in, the
> new driver will be modprobe()'d but the driver core will attach the
> "generic" driver to the device.
>
> After that, nothing will trigger a reprobe when the modprobe()'d device
> driver has finished initialising, as the device has the "generic"
> driver attached to it.
>
> Trigger a reprobe ourselves when new specialised drivers get registered.
>
> Signed-off-by: Bastien Nocera <hadess@xxxxxxxxxx>
> ---
> drivers/usb/core/driver.c | 31 +++++++++++++++++++++++++++++--
> 1 file changed, 29 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
> index f81606c6a35b..a6187dd2186c 100644
> --- a/drivers/usb/core/driver.c
> +++ b/drivers/usb/core/driver.c
> @@ -905,6 +905,30 @@ static int usb_uevent(struct device *dev, struct kobj_uevent_env *env)
> return 0;
> }
>
> +static int __usb_bus_reprobe_drivers(struct device *dev, void *data)
> +{
> + struct usb_device_driver *udriver = to_usb_device_driver(dev->driver);
> + struct usb_device *udev = to_usb_device(dev);
> +
> + if (udriver == &usb_generic_driver &&
> + !udev->use_generic_driver)
> + return device_reprobe(dev);
> +
> + return 0;
> +}
> +
> +static int __usb_device_driver_added(struct device_driver *drv, void *data)
> +{
> + struct usb_device_driver *udrv = to_usb_device_driver(drv);
> +
> + if (udrv->match) {
> + bus_for_each_dev(&usb_bus_type, NULL, udrv,
> + __usb_bus_reprobe_drivers);
What does udrv get used for here?
> + }
> +
> + return 0;
> +}
> +
> /**
> * usb_register_device_driver - register a USB device (not interface) driver
> * @new_udriver: USB operations for the device driver
> @@ -934,13 +958,16 @@ int usb_register_device_driver(struct usb_device_driver *new_udriver,
>
> retval = driver_register(&new_udriver->drvwrap.driver);
>
> - if (!retval)
> + if (!retval) {
> + bus_for_each_drv(&usb_bus_type, NULL, NULL,
> + __usb_device_driver_added);
This looks funny. You're calling both bus_for_each_drv() and
bus_for_each_dev(). Can't you skip this iterator and just call
bus_for_each_dev() directly?
Alan Stern
