Synopsis:
The alsa driver wasn't working, it would only write a partial buffer
before returning from _WriteBytes(). This resulted in an assert for
debug builds and choppy cricket sounds for release builds. The
following patch fixes this by making ALSA write the whole buffer
before returning.
I have noticed that the ALSA driver uses about 100% cpu on my system
when using ALSA as opposed to OSS which uses only about 20%. The
increase is all SYS time as oppose to user time. The user time for
both OSS and ALSA are the same.
Files Modified:
audio/device/platform/unix/audlinux_alsa.cpp
Platforms and Profiles Affected:
linux only.
Branch: HEAD, 150Cay(after branch).
Index: platform/unix/audlinux_alsa.cpp
===================================================================
RCS file: /cvsroot/audio/device/platform/unix/audlinux_alsa.cpp,v
retrieving revision 1.4
diff -u -w -r1.4 audlinux_alsa.cpp
--- platform/unix/audlinux_alsa.cpp 28 Sep 2004 21:04:17 -0000 1.4
+++ platform/unix/audlinux_alsa.cpp 8 Mar 2005 19:48:44 -0000
@@ -856,6 +856,8 @@
int err = 0;
unsigned int frames_written = 0;
snd_pcm_sframes_t num_frames;
+ ULONG32 ulBytesToWrite = ulBuffLength;
+ ULONG32 ulBytesWrote = 0;
lCount = 0;
@@ -874,15 +876,19 @@
return m_wLastError;
}
- num_frames = snd_pcm_bytes_to_frames(m_pAlsaPCMHandle, ulBuffLength);
do
{
+ num_frames = snd_pcm_bytes_to_frames(m_pAlsaPCMHandle, ulBytesToWrite);
err = snd_pcm_writei( m_pAlsaPCMHandle, buffer, num_frames );
+
if (err >= 0)
{
frames_written = err;
- lCount = snd_pcm_frames_to_bytes (m_pAlsaPCMHandle,
frames_written);
+ ulBytesWrote = snd_pcm_frames_to_bytes (m_pAlsaPCMHandle,
frames_written);
+ buffer += ulBytesWrote;
+ ulBytesToWrite -= ulBytesWrote;
+ lCount += ulBytesWrote;
}
else
{
@@ -906,8 +912,9 @@
m_wLastError = RA_AOE_DEVBUSY;
}
}
- } while (err == -EAGAIN);
+ } while (err == -EAGAIN || (err>0 && ulBytesToWrite>0));
+ HX_ASSERT( lCount == ulBuffLength );
return m_wLastError;
}
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