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| author | Max Kellermann <max@duempel.org> | 2013-02-04 15:41:33 +0100 |
|---|---|---|
| committer | Max Kellermann <max@duempel.org> | 2013-02-04 15:51:32 +0100 |
| commit | af9917658145e0595d16c6e508b95d0eef2986d0 (patch) | |
| tree | 7d8e10626142841c63f19e3e2d1bdbde4a1b37fd | |
| parent | 57e825dfe729c80081371d22207b8eb43c49b051 (diff) | |
| download | mpd-af9917658145e0595d16c6e508b95d0eef2986d0.tar.gz mpd-af9917658145e0595d16c6e508b95d0eef2986d0.tar.xz mpd-af9917658145e0595d16c6e508b95d0eef2986d0.zip | |
output/alsa: workaround for noise after manual song change
Workaround for driver bug observed on the Raspberry Pi, see code
comment for details.
| -rw-r--r-- | NEWS | 1 | ||||
| -rw-r--r-- | src/output/AlsaOutputPlugin.cxx | 20 |
2 files changed, 21 insertions, 0 deletions
@@ -11,6 +11,7 @@ ver 0.18 (2012/??/??) - vorbis: accept floating point input samples * output: - new option "tags" may be used to disable sending tags to output + - alsa: workaround for noise after manual song change * improved decoder/output error reporting diff --git a/src/output/AlsaOutputPlugin.cxx b/src/output/AlsaOutputPlugin.cxx index 75089f9d6..1badeb63d 100644 --- a/src/output/AlsaOutputPlugin.cxx +++ b/src/output/AlsaOutputPlugin.cxx @@ -726,6 +726,26 @@ alsa_recover(AlsaOutput *ad, int err) case SND_PCM_STATE_XRUN: ad->period_position = 0; err = snd_pcm_prepare(ad->pcm); + + if (err == 0) { + /* this works around a driver bug observed on + the Raspberry Pi: after snd_pcm_drop(), the + whole ring buffer must be invalidated, but + the snd_pcm_prepare() call above makes the + driver play random data that just happens + to be still in the buffer; by adding and + cancelling some silence, this bug does not + occur */ + alsa_write_silence(ad, ad->period_frames); + + /* cancel the silence data right away to avoid + increasing latency; even though this + function call invalidates the portion of + silence, the driver seems to avoid the + bug */ + snd_pcm_reset(ad->pcm); + } + break; case SND_PCM_STATE_DISCONNECTED: break; |