[Libusbx-devel] Linux patches for 1.0.9 release

[Xiaofan Chen]

On Thu, Mar 29, 2012 at 3:32 PM, Hans de Goede <hdegoede at redhat.com> wrote:
> Hi,
>
>
> On 03/29/2012 01:53 AM, Xiaofan Chen wrote:
>>
>> On Wed, Mar 28, 2012 at 12:33 AM, Pete Batard<pete at akeo.ie>  wrote:
>>>
>>> [1] https://sourceforge.net/apps/trac/libusbx/roadmap
>>>
>>
>> Regarding the roadmap, I would say that we should have
>> a development branch for hot-plug asap to make the
>> Linux and Mac OS X happier since 1.0.10, 1.0.11
>> and 1.0.12 (libusbk integration) are mainly Windows.
>>
>> Hot-plug will be a big thing for all OS.
>>
>> Regarding the HID backend, OpenBSD may be an issue
>> since it only support ugen driver (similar to the older
>> FreeBSD version). For newer FreeBSD version, HPS
>> seems to add a generic ugen interface along with HID
>> interface for generic HID device so that libusb can
>> be used with them. But I have not tested FreeBSD's
>> libusb-1.0 for a while.
>
>
> I don't think we should worry about having a HID backend
> for platforms which have a proper way to get full access
> to USB devices from userspace. AFAIK the windows HID
> backend was done to allow easy access to HID devices
> through libusb without the need to mess with a driver,
> under Linux for example messing with a driver is never
> needed, and AFAIK the same goes for *BSD* and Mac OS X.
>

Not true for Mac OS X. There is no way to detach the
kernel driver using a program. You can use a code-less
kext to achieve the goal though but it is ugly.

+++++
http://www.libusb.org/#CurrentAPIversion:libusb-1.0

On Mac OS X, if an interface driver included with the
OS matches the characteristics of a device, that driver
will seize the interface, and the driver cannot be detached
by libusb, so libusb will not be able to use that interface.
+++++

I believe it is not true for OpenBSD either. You may
have to rebuild the kernel to disable HID (but enable
mouse and keyboard).  That was needed for older
version of FreeBSD to access HID device using
libusb. FreeBsd 8/9 may change that already but
I am not that sure now.

-- 
Xiaofan