[kde-linux] PCM is gone

[Alex Schuster]

Rajko writes:

> On Fri, 3 Aug 2012 03:03:10 +0200
> Alex Schuster <wonko at wonkology.org> wrote:

> > After a reboot, my PCM sound device is gone, kmix no longer shows it,
> > and it is no longer along the available channels in the kmix settings.
> > 
> > I can control PCM with alsamixer, but I'd like to use kmix for that.
> > Any idea what could be wrong?

> To start debugging people should know:
> * Distribution and its release. 
> * KDE version in use. 
> * Application using device and its version. 

D'oh! Um, sorry, yeah, my bad. It's 4.8.4 on Gentoo Linux. About the
application... well, nothing has a problem, it's only that the device does
not show up in kmix.

> Also, there are questions that may follow if above doesn't help:
> * How was missing device discovered; program complaining about, error
>   in the log, ...
> * How was confirmed that device is missing; one program complaining
>   about it means that program can't find device, not that device is
>   missing 

It's not missing, the channel is just no longer being displayed in kmix.
I have it always open on my multimedia desktop, and also use hotkeys
(Ctrl-1 to Ctrl-3) to switch between profiles. But now I have to manage
the PCM device in alsamixer instead.

> Useful is to know, last action before reboot. Actions that may lead to
> missing any device are usually: 
> * package installation, removal, updates (it can change configuration)
> * configuration change by user (which is often done in a file that is
>   changed on program update, not in a file dedicated to user changes)
> * running application that uses such device with admin attributes (which
>   sometimes helps to discover bugs that can't be triggered by normal
>   users, but makes damage in the process)

I did not reboot for a month, and only did so because I had to transport
the PC elsewhere. And I did not log out before for about weeks. With
Gentoo Linux, this means there were a lot of updates in that time that
might somehow be related...

When I had put it back, I got hard drive errors, so I had to replace it.
I restored a recent backup, realized that the replacement drive ALSO has
bad blocks, got yet another drive, restored the backup again, and
everything was back as it should be, except for the PCM sound channel.

	Wonko