[LAU] Jack hanging when a usb soundcard is disconnected

[Len Ovens]

On Sat, 17 Oct 2015, Will Godfrey wrote:

> On Sat, 17 Oct 2015 19:24:02 +0100
> Will Godfrey <willgodfrey at musically.me.uk> wrote:
>
>> On Sat, 17 Oct 2015 13:58:37 -0400
>> Ivica Ico Bukvic <ico at vt.edu> wrote:
>>>
>>> This is a long-standing problem. While it is not intentional, sometimes
>>> newcomers to jack on Linux tend to pull out the soundcard (USB) before
>>> shutting down jack. This results in jack permanently hanging to the
>>> point where one has to force-shutdown the machine. That is at least the
>>> case on Ubuntu 14.04 (and was on 12.04) with lowlatency kernel. Trying
>>> to do sudo killall -9 jackd makes no difference. Essentially, it is
>>> impossible to destroy the process and reboot hangs because of it.
>>>
>>> Any idea what can be done to minimize this problem or alleviate it
>>> altogether?
>>
>> a workaround is from a terminal type:
>>
>> pidof jackd
>>
>> you'll get a number such as 3772
>>
>> then type
>>
>> kill -9 3772
>>

May need to be:
killall -9 jackdbus

Generally, when someone asks they get told:

killall -9 jackd jackdbus

:)

But by default Qjackctl as it comes from ubuntu repos starts jackdbus, not 
jackd.

--
Len Ovens
www.ovenwerks.net