Comment 19 for bug 574137

nohz controls dyntick, aka "tickless kernel". It's an infrastructure to fire the timer only when necessary, thereby lowering power consumption. PulseAudio's default glitch-free mode (tsched=1) was designed to work well with it and, in doing so, exposes a host of hardware and driver bugs.

Disabling high resolution timers forces pulse to fall back to a less precise method of updating buffering.

When you disable pulse, you revert to the older ALSA infrastructure that is interrupt-driven, not timer-driven as pulse uses.

The first thing to test is whether the 21 May snapshot of l-a-d-m in the ppa resolves your symptoms. You need to keep position_fix=1.