[Libdlo] [ANNOUNCE] displaylink-mod-0.3(alpha) (was udlfb)

[Dan]

Roberto De Ioris wrote:
> I do not know why hp and samsung has made this decision, but on linux is
> a pain in the ass setting a configuration for usb devices as the host
> controller driver get the most useful one using an (IMHO totally wrong)
> algorithm.
>
> The only (raw) solution i found is to unload the usbhid module, then set
> the first configuration for the usb device using /sys (look for the file
> bConfigurationValue, it must contain '1' and not '2') and then reload
> the displaylink module.
>
> I must admit that i have no experience on multiple configuration usb
> device, so probably someone could point me to a real solution.
>   
Bernie's given a very thorough rationale for the basis of this design - 
it does make a bit harder for linux unfortunately.

The libdlo code calls usb_detach_kernel_driver_np, this in turn calls 
http://lxr.linux.no/linux+v2.6.30/drivers/usb/core/devio.c#L1465 .

Maybe you can use this code? As a VID/PID match your probe call should 
trump the HID class driver, and when the driver loads it should be able 
to dislodge an existing driver.

Configuration #1 is always the video configuration, #2 which is listed 
first in the list of configurations (and therefore generally chosen by 
the OS by default) is used to allow drivers to install on Windows.

When in configuration #1, interface 0 is always the video interface. 
There may be a HID interface on another interface in configuration #1.

cheers,

Dan.