alsamixer -c0 Selecting the master channel and pressing "m" to mute it and then unmute it has the same effect. It's an ALSA driver bug in snd-hda-intel.
** Changed in: linux (Ubuntu) Status: Incomplete => Confirmed -- Muting and unmuting Master channel when headphones are plugged in causes internal speaker to unmute on MacBook Pro https://bugs.launchpad.net/bugs/212051 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs