device filtering support

[Travis]

On 2/7/2012 4:48 PM, Segher Boessenkool wrote:
>>> The firmware is buggy since after it transfers some endpoint data
>>> and then all subsequent device descriptor request will fail and then
>>> the device goes to an unstable state.
>>>
>>> We changed libusb-win32 driver in 1.2.5.0 to cache the
>>> device descriptor to solve the issue.
>>
>> Is compensating for buggy firmwares something we really want to 
>> consider doing with libusbx?
>
> Not at all costs no.  But it would be good if libusbx worked with
> not-fully-standard-compliant devices: there aren't very many devices
> that *are* standard compliant in all details!
>
> If we do weird things no one else does, it has a bigger chance of
> hitting a bug on a device.  So we should try to avoid asking for
> the device descriptor a zillion times, since no OS does that, so
> it isn't tested.

I agree, I only feel slightly more strongly about it.  I think it is 
good to support as many non-compliant devices as possible.  I also think 
these extra requests would cause problems for some of the firmware based 
usb devices that are not fully USB compliant.

>   It's also a rather stupid thing to do in any
> case ;-)
>
>

Crazy even.. ;)

Regards,
Travis