diff options
| -rw-r--r-- | src/output/plugins/AlsaOutputPlugin.cxx | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/src/output/plugins/AlsaOutputPlugin.cxx b/src/output/plugins/AlsaOutputPlugin.cxx index 4cf0c3bd2..8f32cf8d7 100644 --- a/src/output/plugins/AlsaOutputPlugin.cxx +++ b/src/output/plugins/AlsaOutputPlugin.cxx @@ -147,6 +147,16 @@ class AlsaOutput final */ bool must_prepare; + /** + * Has snd_pcm_writei() been called successfully at least once + * since the PCM was prepared? + * + * This is necessary to work around a kernel bug which causes + * snd_pcm_drain() to return -EAGAIN forever in non-blocking + * mode if snd_pcm_writei() was never called. + */ + bool written; + bool drain; /** @@ -305,9 +315,11 @@ private: auto frames_written = snd_pcm_writei(pcm, period_buffer.GetHead(), period_buffer.GetFrames(out_frame_size)); - if (frames_written > 0) + if (frames_written > 0) { + written = true; period_buffer.ConsumeFrames(frames_written, out_frame_size); + } return frames_written; } @@ -673,6 +685,7 @@ AlsaOutput::Open(AudioFormat &audio_format) active = false; must_prepare = false; + written = false; error = {}; } @@ -705,6 +718,7 @@ AlsaOutput::Recover(int err) noexcept case SND_PCM_STATE_SETUP: case SND_PCM_STATE_XRUN: period_buffer.Rewind(); + written = false; err = snd_pcm_prepare(pcm); break; case SND_PCM_STATE_DISCONNECTED: @@ -755,6 +769,11 @@ AlsaOutput::DrainInternal() return period_buffer.IsEmpty(); } + if (!written) + /* if nothing has ever been written to the PCM, we + don't need to drain it */ + return true; + /* .. and finally drain the ALSA hardware buffer */ int result; @@ -914,6 +933,7 @@ try { if (must_prepare) { must_prepare = false; + written = false; int err = snd_pcm_prepare(pcm); if (err < 0) |