After the upgrade of desktops from bullseye to bookworm with cinnamon
as desktop environment the bell character in a shell does not produce
a sound.

Type in a bash in xterm or gnome-terminal :

echo -e '\a'

With environments older that bookworm this would sound a beep or bell
via the pcspkr kernel module.

With the new cinnamon there is only silence.
The pcspkr module is loaded but no bell sounds.

Regards
Christoph

Hi Christoph,

Sorry for the long delay. This is a deliberate change in muffin, and it
is not specific to Debian.

In muffin 4.8 (bullseye) the window manager only subscribed to XKB bell
events and left the X server's audible bell alone, so the pcspkr beep
kept working. Since muffin 5.x (bookworm) the code follows mutter and
disables it explicitly — XkbChangeEnabledControls(...,
XkbAudibleBellMask, 0)
in src/x11/meta-x11-display.c — because the window manager now intends to
play the bell itself. It only does so when the audible-bell key is set,
and that key defaults to false, so nothing is played and the hardware
beep is gone: silence.

You can get a bell sound back by enabling "Enable audio alerts" in System
Settings > Accessibility, or equivalently:

gsettings set org.cinnamon.desktop.wm.preferences audible-bell true

muffin then plays /usr/share/cinnamon/sounds/bell.ogg (from
cinnamon-common); the sound file is selectable in the same settings page.
This does not bring back the pcspkr beep, which stays disabled by the
window manager for the whole session.

The code is in muffin and is unchanged in current versions, so I'm
reassigning the bug there and forwarding it upstream: muffin has a
fallback that would force the classic bell when playing the sound fails
(XkbForceDeviceBell in src/x11/events.c), but it never triggers, because
bell_audible_notify() always reports success and is only reached when
audible-bell is already true.