Re: [Libusb-devel] Patch: libusb/os/linux_usbfs.c: Distingush between usbfs and other kernel mode drivers

[Xiaofan C. <xia...@gm...>]

On Thu, Oct 7, 2010 at 2:31 AM, Alan Stern <st...@ro...> wrote:
> As far as Linux goes, that's sort of right.  One driver isn't
> considered "better" than another in any particular way.  When the
> system looks for a driver for a device, it probes all the drivers it
> can find that match the device's or interface's descriptors, until one
> of the probes succeeds.  This is done in the order the drivers were
> registered with the kernel's driver core, complicated by the fact that
> drivers can be loaded dynamically in response to device-detection
> events and unloaded manually by the user.
>
> Thus the "best" driver isn't necessarily _better_ than any other, in
> any meaningful sense.  It simply is the one that was registered
> earliest.
>
> Of course, this means that if you detach a device's driver and then
> tell the kernel to reattach a driver, under normal conditions you will
> get the same driver as before -- which means the overall effect is the
> same as what Tim described.

In that case, I think it is better to have the option of attaching
a driver which the user wants.

I mean it would be good to extend the following two API
or new APIs.

1) libusb_kernel_driver_active() can have options to return
the driver name, just like the 0.1 API usb_get_driver_np().
Or we can have new API for this purpose. I think extending
this API is probably better.

2) libusb_attach_kernel_driver() can be extended to take the driver
name as a parameter so that user can specify the
driver they want the kernel to attach.


-- 
Xiaofan