Unblock sound on resume in Linux Mint

On the ThinkPad T60p and T61, using Linux Mint 17 and later (and probably Ubuntu 16.04 or later), sound is not properly initialized after a suspend/resume cycle. The symptom is that after a resume, playing a video on YouTube produces no sound. The fix is to play a sound file using the /usr/bin/play utility (part of the sox package), which unblocks or reinitializes the audio device.

On Mint 17, to make the fix run automatically after a resume, become root (sudo su) and create the executable script /usr/lib/pm-utils/sleep.d/48sound with the following contents:

#!/bin/sh
# sound - play a sound after resume to unblock sound device.

# . "${PM_FUNCTIONS}"

case $1 in
	hibernate|suspend)
		;;

	thaw|resume)
		/usr/bin/play -q /usr/share/sounds/linuxmint-gdm.wav
		echo "48sound resuming!" >/tmp/sound.log
		;;

	*) exit $NA
		;;
esac

exit 0

Make the script executable using chmod +x /usr/lib/pm-utils/sleep.d/48sound.

On Mint 18 and later, suspend is handled by systemd and the above script won’t run. Instead, create the executable script /lib/systemd/system-sleep/sound as root with the following contents:

#!/bin/sh

case $1 in
  post)
    /usr/bin/play -q /usr/share/sounds/linuxmint-gdm.wav
    ;;
esac

Use chmod +x /lib/systemd/system-sleep/sound to make the script executable.

This fix produces an innocuous short beep on resume.