SF patch #489989 (Charles G Waldman) linuxaudiodev.c - fix initialization

The OSS Programmer's Reference (www.4front-tech.com)
states:

*Setting Sampling Parameters

There are three parameters which affect the sound
quality (and therefore memory and bandwidth
requirements) of sampled audio data. These are:

** sample format (sometimes called number of bits)
** number of channels (mono or stereo), and
** sampling rate (speed)

NOTE:

It is important to always set these parameters in the
above order. Setting sampling rate before the number
of channels doesn't work with all devices.

diff --git a/Modules/linuxaudiodev.c b/Modules/linuxaudiodev.c
index 37ad5ff4c612346205b3293903ce9ef2add50f3e..e0f144bb8578a974a99a20907935a1868cf3df5d 100644 (file)
--- a/Modules/linuxaudiodev.c
+++ b/Modules/linuxaudiodev.c
@@ -258,15 +258,6 @@ lad_setparameters(lad_t *self, PyObject *args)
        return NULL;
     }
 
-    if (ioctl(self->x_fd, SNDCTL_DSP_SPEED, &rate) == -1) {
-        PyErr_SetFromErrno(LinuxAudioError);
-        return NULL;
-    }
-    if (ioctl(self->x_fd, SNDCTL_DSP_CHANNELS, &nchannels) == -1) {
-        PyErr_SetFromErrno(LinuxAudioError);
-        return NULL;
-    }
-
     for (n = 0; n < n_audio_types; n++)
         if (fmt == audio_types[n].a_fmt)
             break;
@@ -294,6 +285,14 @@ lad_setparameters(lad_t *self, PyObject *args)
         PyErr_SetFromErrno(LinuxAudioError);
         return NULL;
     }
+    if (ioctl(self->x_fd, SNDCTL_DSP_CHANNELS, &nchannels) == -1) {
+        PyErr_SetFromErrno(LinuxAudioError);
+        return NULL;
+    }
+    if (ioctl(self->x_fd, SNDCTL_DSP_SPEED, &rate) == -1) {
+        PyErr_SetFromErrno(LinuxAudioError);
+        return NULL;
+    }
 
     Py_INCREF(Py_None);
     return Py_None;