System bell randomly doesn't work after login

[Graeme Hewson]

In KDE System Settings / Accessibility I have "Use system bell" ticked. I have commented out the entry for pcspkr in /etc/modprobe.d/blacklist.conf.

I can get a beep from the PC speaker using xterm and entering, for instance, ^G, or backspace, or "echo -e '\a'". (Konsole, of course, usually doesn't use the system bell.)

However, quite often after logging in to a KDE session, whether or not that's immediately after booting, the beep doesn't work, and the only way to restore it is to go to Accessibility settings, untick "Use system bell", click Apply, re-tick "Use system bell" and click Apply again.

The problem doesn't seem to be just some corrupted KDE setting, because it can happen if I use a test account and before logging in to KDE, use a TTY session to delete .kde/ or even everything in the home directory (using "cd; find . -delete). If I do this, sometimes the speaker works (which it should, since this is the default setting), and sometimes it doesn't. I can't find a pattern.

Once the speaker is working in a session, though, it continues to work. The problem only happens around login.

This happens with Kubuntu 13.10 and 12.04.3 LTS. The problem is confined to Kubuntu – it doesn't occur in other distributions I've tried:

Debian Testing with kernel 3.11.2 and KDE 4.11.3
OpenSUSE 13.1 (KDE 4.11.2)
PC-BSD 9.2 (KDE 4.10.5)

I tried using KDM instead of LightDM for 13.10, though 12.04 uses KDM anyway. No difference.

Always, even when the bell isn't working, "xset q" shows:
  bell percent: 50 bell pitch: 400 bell duration: 100

I haven't seen any relevant messages in .xsession-errors. I can't see anything related to system bell or PC speaker in KDebugDialog.

[Graeme Hewson (ghewson)]

The "beep" command always works, even when the KDE system bell doesn't.

The udev information for the speaker is the same whether or not the KDE system bell is working. I have the problem on the two PCs I have here. I'll upload the udev information for one of them; the information for the other is the same except for a different event number.

[Graeme Hewson (ghewson)]

Slight correction: readline generates the sound when Backspace at the beginning of a line or ^G is pressed, but it only does this by default; there's no sound if /etc/inputrc has bell-style set to other than "audible".

The problem is still present testing only with "echo -e '\a'".