The mic pump's WASAPI backend rendered silence into the virtual mic's
render endpoint (typically the Steam Streaming Microphone) for the whole
host lifetime. A RUNNING stream makes the Windows audio stack hold a
kernel power request ("An audio stream is currently in use", visible in
powercfg /requests), so every idle Punktfunk host blocked system sleep
forever — field-reported 2026-08-12 ("doesn't go to sleep anymore since
installing punktfunk; powercfg shows the Steam Streaming Microphone").
Stop the render stream (IAudioClient::Stop — client stays initialized,
the mic endpoint keeps existing) after 10 s of silence-only output at an
unchanged queue length, and park the render thread on a condvar the
producer notifies on the empty->non-empty edge, so the next mic frame
resumes the stream within one device period — well under the jitter
buffer's prime depth, so nothing audible changes. Keying the idle window
on the queue LENGTH (not emptiness) also covers a sub-prime tail a
vanished client left behind, while any fresh burst moves the length and
resets the window instead of being dropped.
During a session the box stays awake through the session's own
DisplayWakeRequest (pf-frame), never through this silence.
PUNKTFUNK_MIC_ALWAYS_ON=1 restores the old always-running stream in case
a virtual audio driver misbehaves while its render side is paused.
enricobuehler
535e95c4c0