Preface: I ran into a sound card crackling issue a while back and wrote a post about it: Fixing crackling from an external USB sound card on a ThinkPad X1 Carbon via Thunderbolt Dock Tried that method, and it turned out to be pretty much useless. Basically, every time I plug in the Thunderbolt 3 dock, TLP just doesn’t apply the “power-saving exclusion” setting to the corresponding device.

I had a really weird problem, and it haunted me for about a year. At home my laptop sits in a Thunderbolt 3 dock, and on that dock I plugged in a USB DAC to make sure my desk has a headphone output, plus that USB DAC also feeds two speakers. Short version: I don’t use the dock’s built-in audio. I added a separate USB DAC on top. Starting last year, that DAC began acting up in a strange way: whenever I played music or video, the sound would crackle. At first I blamed the dock, but plugging the DAC straight into the laptop’s USB port made the problem disappear. It only happened when it was plugged into the dock, which pointed to a power-delivery issue.