Re: Mac OS real USB device support issue

[Programmingkid]

> On Apr 9, 2021, at 4:08 AM, Gerd Hoffmann <gerd@kraxel.org> wrote:
> 
>  Hi,
> 
>> The questions that come to mind are:
>> - Does libusb_detach_kernel_driver() work on Mac OS?
>> - Is libusb_detach_kernel_driver() called on Mac OS in QEMU?
>> 
>> The only mention of this function in QEMU comes from host-libusb.c. 
>> 
>> After some tests I found out the function
>> host-libusb.c:usb_host_detach_kernel() is being called on Mac OS 11.1.
>> It never reaches the libusb_detach_kernel_driver() function. It stops
>> at the continue statement.
> 
> Yep.  Most likely libusb_kernel_driver_active() returns 0 because the
> kernel driver management functions are not implemented for macos.
> 
> take care,
>  Gerd
> 

I was wondering about the usb_host_detach_kernel() code. It iterates thru 
interface 0 to 15. Why does it stop at 15? Isn't possible to have up to 255 
interfaces?