Getting the same effect on 12.04 , started happening after some update in 2013 january When i plug in headphones or pull them out then the machine goes on mute and i have to restore the sound from alsamixer $ dpkg -l | grep alsa ii alsa-base 1.0.25+dfsg-0ubuntu1 ALSA driver configuration files ii alsa-utils 1.0.25-1ubuntu5 Utilities for configuring and using ALSA $ dpkg -l | grep pulse ii gstreamer0.10-pulseaudio 0.10.31-1ubuntu1 GStreamer plugin for PulseAudio ii libcanberra-pulse 0.28-3ubuntu3 PulseAudio backend for libcanberra ii libpulse-mainloop-glib0 1:1.1-0ubuntu15.2 PulseAudio client libraries (glib support) ii libpulse-mainloop-glib0:i386 1:1.1-0ubuntu15.2 PulseAudio client libraries (glib support) ii libpulse0 1:1.1-0ubuntu15.2 PulseAudio client libraries ii libpulse0:i386 1:1.1-0ubuntu15.2 PulseAudio client libraries ii libpulsedsp 1:1.1-0ubuntu15.2 PulseAudio OSS pre-load library ii libpulsedsp:i386 1:1.1-0ubuntu15.2 PulseAudio OSS pre-load library rc libsdl1.2debian-pulseaudio 1.2.14-6.1ubuntu4 Simple DirectMedia Layer (with X11 and PulseAudio options) ii pulseaudio 1:1.1-0ubuntu15.2 PulseAudio sound server ii pulseaudio-esound-compat 1:1.1-0ubuntu15.2 PulseAudio ESD compatibility layer ii pulseaudio-module-bluetooth 1:1.1-0ubuntu15.2 Bluetooth module for PulseAudio sound server ii pulseaudio-module-gconf 1:1.1-0ubuntu15.2 GConf module for PulseAudio sound server ii pulseaudio-module-x11 1:1.1-0ubuntu15.2 X11 module for PulseAudio sound server ii pulseaudio-utils 1:1.1-0ubuntu15.2 Command line tools for the PulseAudio sound server ii vlc-plugin-pulse 2.0.5-0ubuntu0.12.04.1 PulseAudio plugin for VLC $ cat /proc/asound/cards 0 [Generic ]: HDA-Intel - HD-Audio Generic HD-Audio Generic at 0xf0444000 irq 53 1 [Generic_1 ]: HDA-Intel - HD-Audio Generic HD-Audio Generic at 0xf0440000 irq 16 it seems that card 0 is my ati hdmi and card 1 is the actual soundcard on the motherboard Laptop : HP Pavilion dv6 $ lspci -v | grep Audio -A2 00:01.1 Audio device: Advanced Micro Devices [AMD] nee ATI BeaverCreek HDMI Audio [Radeon HD 6500D and 6400G-6600G series] Subsystem: Hewlett-Packard Company Device 358d Flags: bus master, fast devsel, latency 0, IRQ 53 -- 00:14.2 Audio device: Advanced Micro Devices [AMD] Hudson Azalia Controller (rev 01) Subsystem: Hewlett-Packard Company Device 358d Flags: bus master, slow devsel, latency 32, IRQ 16 ---