"...issue is that on certain systems' PS/2 keyboards, the volume control keys (and certain media keys) report a KEY_DOWN when they're pressed, but not a KEY_UP when they're released..."
only difference are non-Dell laptops (Compaq, HP, Toshiba among others) and Fn volume keys
I would argue that bug #271706 should be marked duplicate of this because symptoms are identical and the cause same:
https:/ /bugs.launchpad .net/ubuntu/ +bug/278781/ comments/ 7
"...issue is that on certain systems' PS/2 keyboards, the volume control keys (and certain media keys) report a KEY_DOWN when they're pressed, but not a KEY_UP when they're released..."
only difference are non-Dell laptops (Compaq, HP, Toshiba among others) and Fn volume keys