fix(alsa): stop flooding error callback during timestamp startup transient#1116
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roderickvd merged 2 commits intomasterfrom Mar 2, 2026
Merged
fix(alsa): stop flooding error callback during timestamp startup transient#1116roderickvd merged 2 commits intomasterfrom
roderickvd merged 2 commits intomasterfrom
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Some ALSA backends (notably the PulseAudio ALSA plugin on Raspberry Pi) return a valid htstamp before the stream is triggered but then return (0, 0) for the first several periods after it starts. This caused a flood of "get_htstamp was earlier than get_trigger_htstamp" errors on every audio callback until the timestamps stabilised. Store a fallback Instant at stream creation and use it silently whenever hardware timestamp computation fails, rather than routing the transient error through the user's error callback. Fixes RustAudio/rodio#853
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Attempt to fix RustAudio/rodio#853, where a user on Raspberry Pi was seeing 80 copies of:
The 80 messages then stopped and audio worked fine. So it's a startup thing, not a permanent failure.
What may be happening: the timestamp detection at stream creation checks
get_htstamp()while the PCM is still inPREPAREDstate. At that point the PulseAudio ALSA plugin returns a valid-looking wall clock, so we decide "hardware timestamps work, use them." But for the first N periods after the stream is triggered,htstampcomes back as(0, 0), which is earlier thantrigger_htstampand causes the error.The fix is to always store a fallback Instant at creation and use it silently when hardware timestamp computation fails, instead of routing the transient failure through the error callback. Once the hardware timestamps stabilise (which they do, quickly) the hardware path takes over automatically and the fallback is never touched again.