[Spice-devel] Native USB redirection does not work - (remote-viewer) did not claim interface 0 before use

[Hans de Goede]

Hi,

On 12/03/2012 09:40 PM, Sigbjorn Lie wrote:
> On 12/02/2012 11:58 AM, Hans de Goede wrote:
>> Hi,
>>
>> On 11/30/2012 03:40 PM, Sigbjorn Lie wrote:
>>> Hi,
>>>
>>> I have disabled pcscd with chkconfig and rebooted. After the reboot I attempted to connect to the
>>> VDI and share my smart card reader again. The same issue occured.
>>
>>
>> ifdhandler is still messing with the reader while spice tries to use it, I would have expected the
>> stopping of pcscd to also stop ifdhandler, but it seems I was wrong. Please also disable ifdhandler,
>> I suspect that will solve your issue.
>>
>
> And that worked just fine.  I can forward my smart card reader to the Win 7 VDI now. Thank you.
>

Good!

> Would you consider this to be a bug?
>

Yes, I think what you are seeing is in essence the same as:
https://bugzilla.redhat.com/show_bug.cgi?id=820205

With this libusb bug fixed, and assuming that ifdhandler properly claims the device, you should
get a "device is busy" instead when you try to redirect the device when it is used by ifdhandler.

I'm afraid that unlike devices which use kernel drivers, there is no reliable way to take-over
the device from a userspace driver like ifdhandler, so the busy error is the best we can do.

Note that for smartcards the smartcard channel is a much better solution though, as it allows
use of the card in both the client and guest simultaneously.

Regards,

Hans