With kernel 5.12-rc2 (and torvalds/master 144c79ef3353), if mpd is playing or paused when my system is suspended-to-ram, when the system is resumed mpd will consume ~200% CPU until killed. It continues to produce audio and respond to pause/play commands, which do not affect CPU usage. This occurs with either pulse (to PulseAudio or PipeWire-as-PulseAudio) or alsa audio_output.
The issue appears to have been introduced by a combination of two commits: 3bfe6106693b caused freeze on suspend-to-ram when mpd is paused or playing. e4b4a13f4941 fixed suspend-to-ram, but introduced the high CPU on resume. I attempted to further diagnose using `perf record -p $(pidof mpd)`. Running for about a minute after resume shows ~280 MMAP2 events and almost nothing else. I'm not sure what to make of that or how to further investigate. Let me know if there's anything else I can do to help diagnose/test. Thanks, Kevin