Misc improvement for PCM

- Allow user to pass the PCM name to open via ALSA_OSS_PCM_DEVICE
  environment variable.
- Always open the device with non-blocking mode, and change the
  mode to the proper one after open.
- Code clean up.

diff --git a/alsa/pcm.c b/alsa/pcm.c
index d8d76446b5d3cecf011673a203a18bebecfed9df..8aea2f688427ab98d50af70770a394ff0aa86d58 100644 (file)
--- a/alsa/pcm.c
+++ b/alsa/pcm.c
@@ -471,6 +471,31 @@ int lib_oss_pcm_close(int fd)
        return 0;
 }
 
+static int open_pcm(oss_dsp_t *dsp, const char *name, unsigned int pcm_mode,
+                   unsigned int streams)
+{
+       int k, result;
+
+       result = -ENODEV;
+       for (k = 0; k < 2; ++k) {
+               if (!(streams & (1 << k)))
+                       continue;
+               result = snd_pcm_open(&dsp->streams[k].pcm, name, k, SND_PCM_NONBLOCK);
+               DEBUG("Opened PCM %s for stream %d (result = %d)\n", name, k, result);
+               if (result < 0) {
+                       if (k == 1 && dsp->streams[0].pcm != NULL) {
+                               dsp->streams[1].pcm = NULL;
+                               streams &= ~(1 << SND_PCM_STREAM_CAPTURE);
+                               result = 0;
+                       }
+                       break;
+               } else if (! pcm_mode)
+                       /* reset the blocking mode */
+                       snd_pcm_nonblock(dsp->streams[k].pcm, 0);
+       }
+       return result;
+}
+
 static int oss_dsp_open(int card, int device, int oflag, mode_t mode)
 {
        oss_dsp_t *dsp;
@@ -552,39 +577,21 @@ static int oss_dsp_open(int card, int device, int oflag, mode_t mode)
                if (result < 0)
                        goto _error;
        }
-       for (k = 0; k < 2; ++k) {
-               if (!(streams & (1 << k)))
-                       continue;
-               result = snd_pcm_open(&dsp->streams[k].pcm, name, k, pcm_mode);
-               if (result < 0) {
-                       if (k == 1 && dsp->streams[0].pcm != NULL) {
-                               dsp->streams[1].pcm = NULL;
-                               streams &= ~(1 << SND_PCM_STREAM_CAPTURE);
-                               result = 0;
-                       }
-                       break;
-               }
-       }
+       s = getenv("ALSA_OSS_PCM_DEVICE");
+       result = -ENODEV;
+       if (s && *s)
+               result = open_pcm(dsp, s, pcm_mode, streams);
+       if (result < 0)
+               result = open_pcm(dsp, name, pcm_mode, streams);
        if (result < 0) {
-               result = 0;
-               for (k = 0; k < 2; ++k) {
-                       if (dsp->streams[k].pcm) {
-                               snd_pcm_close(dsp->streams[k].pcm);
-                               dsp->streams[k].pcm = NULL;
-                       }
-               }
                /* try to open the default pcm as fallback */
                if (card == 0 && (device == OSS_DEVICE_DSP || device == OSS_DEVICE_AUDIO))
                        strcpy(name, "default");
                else
                        sprintf(name, "plughw:%d", card);
-               for (k = 0; k < 2; ++k) {
-                       if (!(streams & (1 << k)))
-                               continue;
-                       result = snd_pcm_open(&dsp->streams[k].pcm, name, k, pcm_mode);
-                       if (result < 0)
-                               goto _error;
-               }
+               result = open_pcm(dsp, name, pcm_mode, streams);
+               if (result < 0)
+                       goto _error;
        }
        result = oss_dsp_params(dsp);
        if (result < 0)