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fix: suspend PipeWire sink before ALSA Direct to prevent DeviceBusy on first play

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When switching from PipeWire to ALSA Direct, PipeWire holds the ALSA
device open causing EBUSY on the first snd_pcm_open. Now detects
DeviceBusy, suspends the PipeWire sink via pactl, waits 200ms for
release, then retries. Applied to both hw and plughw paths.
This commit is contained in:
vicrodh committed 2026-02-28 07:48:03 -06:00
1 parent 199f19a426
commit fe3c5b0528
1 file changed
+61 -1
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crates/qbz-audio/src/alsa_backend.rs
+61 -1
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@@ -462,8 +462,43 @@ impl AlsaBackend {
let error = super::backend::AlsaDirectError::from_alsa_error(&e);
log::warn!("[ALSA Backend] hw attempt failed: {}", error);
if matches!(error, super::backend::AlsaDirectError::DeviceBusy(_)) {
// PipeWire may be holding the ALSA device open.
// Suspend PipeWire sinks to release the device, then retry.
log::info!("[ALSA Backend] Device busy — suspending PipeWire sinks to release ALSA device");
if let Ok(output) = std::process::Command::new("pactl")
.args(["suspend-sink", "@DEFAULT_SINK@", "1"])
.output()
{
if output.status.success() {
log::info!("[ALSA Backend] PipeWire sink suspended, waiting for device release...");
std::thread::sleep(std::time::Duration::from_millis(200));
match super::AlsaDirectStream::new(&hw_device, config.sample_rate, config.channels) {
Ok(stream) => {
log::info!("[ALSA Backend] ✓ Direct hw stream created after PipeWire suspend");
return Some(Ok((stream, super::backend::BitPerfectMode::DirectHardware)));
}
Err(e2) => {
log::warn!("[ALSA Backend] Retry after suspend also failed: {}", e2);
}
}
} else {
let stderr = String::from_utf8_lossy(&output.stderr);
log::warn!("[ALSA Backend] Failed to suspend PipeWire sink: {}", stderr);
}
}
// If retry failed or suspend failed, fall through to error
log::error!("[ALSA Backend] Cannot acquire device even after PipeWire suspend");
return Some(Err(format!(
"ALSA Direct failed: {}. Device may be in use or inaccessible.",
error
)));
}
if !error.allows_plughw_fallback() {
// Non-recoverable error (busy, permissions, etc.)
// Non-recoverable error (permissions, etc.)
log::error!("[ALSA Backend] Cannot fallback - error type: {:?}", error);
return Some(Err(format!(
"ALSA Direct failed: {}. Device may be in use or inaccessible.",
@@ -490,6 +525,31 @@ impl AlsaBackend {
Some(Ok((stream, super::backend::BitPerfectMode::PluginFallback)))
}
Err(e) => {
let error = super::backend::AlsaDirectError::from_alsa_error(&e);
if matches!(error, super::backend::AlsaDirectError::DeviceBusy(_)) {
log::info!("[ALSA Backend] plughw device busy — suspending PipeWire sinks to release ALSA device");
if let Ok(output) = std::process::Command::new("pactl")
.args(["suspend-sink", "@DEFAULT_SINK@", "1"])
.output()
{
if output.status.success() {
log::info!("[ALSA Backend] PipeWire sink suspended, retrying plughw...");
std::thread::sleep(std::time::Duration::from_millis(200));
match super::AlsaDirectStream::new(&plughw_device, config.sample_rate, config.channels) {
Ok(stream) => {
log::info!("[ALSA Backend] ✓ plughw stream created after PipeWire suspend");
return Some(Ok((stream, super::backend::BitPerfectMode::PluginFallback)));
}
Err(e2) => {
log::error!("[ALSA Backend] plughw retry after suspend also failed: {}", e2);
}
}
}
}
}
log::error!("[ALSA Backend] plughw fallback also failed: {}", e);
Some(Err(format!(
"Bit-perfect playback could not be established. hw failed, plughw failed: {}",