What to do if USB stack seems dead

[Hans Petter Selasky]

On 09/08/14 22:40, Ian Lepore wrote:
> On Sat, 2014-09-06 at 23:21 +0200, Hans Petter Selasky wrote:
>> On 09/06/14 21:57, Maxim V FIlimonov wrote:
>>> Lately, I've been heavily experimenting with different USB devices (for
>>> instance, USB to TTL one, but that's another story), and at a moment I
>>> encountered that the system doesn't react on new USB devices connected. The
>>> connected devices work fine, though. The question is: what can I do in such a
>>> case if I don't want to reboot my box?
>>>
>>
>> Hi,
>>
>> If a TTY port is not closed, it will prevent other USB devices on that
>> particular USB controller from enumerating.
>>
>> --HPS
>
> What does that mean, "is not closed"?  You mean if I have any usb-serial
> adapter tty device open, other device insert/remove events aren't
> handled?
>
> Or that if a usb-serial device is removed while the device is open, that
> prevents other insert/remove events?
>
> -- Ian

Yes, because we need to wait for some refcounting inside the TTY layer 
at detach when the TTY device is open at detach. It is not a USB stack 
problem.

--HPS