[Libusbx-devel] Linux patches for 1.0.9 release

[Hans de Goede]

Hi,

On 03/29/2012 02:32 PM, Xiaofan Chen wrote:
> On Thu, Mar 29, 2012 at 8:09 PM, Xiaofan Chen<xiaofanc at gmail.com>  wrote:
>> On Thu, Mar 29, 2012 at 3:32 PM, Hans de Goede<hdegoede at redhat.com>  wrote:
>>> 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.
>> +++++
>
> More details here. Nathan did not like the idea
> and closed the ticket as invalid.
> http://www.libusb.org/ticket/33
>
> Also here.
> http://www.libusb.org/wiki/FAQ#CanIcreateadriverlessdeviceusingHIDclass
> "On Mac OS X you must install a codeless kext kernel driver and
> then reboot, before you can communicate with the device."
>
> On certain Mac OS X version, the code-less kext may
> not work well.

AFAIK Mac OS X does have a call to ask the driver to release
the device, but the driver may refuse ...

>> 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.
>
> For OpenBSD the price you pay is to lose your
> USB mouse and keyboard in order to use libusb
> (based on ugen driver).
>
> http://www.apcupsd.com/manual/manual.html#platform-support
> ++++++
> OpenBSD
> (you will lose use of USB keyboard and mouse):
> Disable: uhidev, ums, wsmouse, ukbd, wskbd, uhid
> Enable: ugen
> +++++

Suck, time to fix OpenBSD?

Regards,

Hans