On Fri, 2020-07-24 at 13:32 +0300, Andy Shevchenko wrote:
> On Fri, Jul 24, 2020 at 12:03 PM Bastien Nocera <hadess@xxxxxxxxxx>
> 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.
>
> ...
>
> > +static int __usb_bus_reprobe_drivers(struct device *dev, void
> > *data)
> > +{
> > + struct usb_device_driver *new_udriver = data;
> > + struct usb_device_driver *udriver;
> > + struct usb_device *udev;
> > +
> > + if (!dev->driver)
> > + return 0;
> > +
> > + udriver = to_usb_device_driver(dev->driver);
> > + if (udriver != &usb_generic_driver)
> > + return 0;
>
> What about
>
> static bool is_dev_usb_generic_driver(dev)
> {
> struct usb_device_driver *udd = dev->driver ?
> to_usb_device_driver(dev->driver) : NULL;
>
> return udd == &usb_generic_driver;
> }
>
> if (!is_dev_usb_generic_driver)
> return 0;
>
> ?
Great, done locally.
> > + udev = to_usb_device(dev);
> > + if (usb_device_match_id(udev, new_udriver->id_table) !=
> > NULL ||
> > + (new_udriver->match && new_udriver->match(udev) == 0))
> > + device_reprobe(dev);
> > +
> > + return 0;
>
> What about
>
> udev = to_usb_device(dev);
> if (usb_device_match_id(udev, new_udriver->id_table) == NULL)
> return 0;
> ?
>
> if (new_udriver->match && new_udriver->match(udev) == 0))
> device_reprobe(dev);
> return 0;
That's not the same conditionals. If there's ->match but no matching
->id_table, you're not going to reprobe, when we'd want to.
> > +}
>
> ...
>
> > + /* Check whether any device could be better served
> > with
> > + * this new driver
> > + */
>
> Comment style?
Fixed locally.
> ...
>
> > + if (new_udriver->match || new_udriver->id_table)
>
> But match check is incorporated in the loop function.
It's ->match || ->id_table, not simply ->match. Drivers can have
either, and we need to reprobe if either of those are present (and
we're also checking in the function to avoid calling a NULL pointer ;)
> > + bus_for_each_dev(&usb_bus_type, NULL,
> > new_udriver,
> > + __usb_bus_reprobe_drivers)
> > ;
