Make sure we always have a sensible channel mapping

If PA doesn't know a default channel map for the specified number of channels,
synthesize one by extending a known one with a smaller channel number.

diff --git a/pulse/pcm_pulse.c b/pulse/pcm_pulse.c
index 6d7403c16213008d67660fe8784564045d81a6e9..5a5b95434e9a91be163403c349c79e55ec214d48 100644 (file)
--- a/pulse/pcm_pulse.c
+++ b/pulse/pcm_pulse.c
@@ -485,6 +485,7 @@ static int pulse_prepare(snd_pcm_ioplug_t * io)
        pa_channel_map map;
        snd_pcm_pulse_t *pcm = io->private_data;
        int err = 0, r;
+       unsigned c, d;
 
        assert(pcm);
        assert(pcm->p);
@@ -505,22 +506,22 @@ static int pulse_prepare(snd_pcm_ioplug_t * io)
 
        assert(pcm->stream == NULL);
 
+       for (c = pcm->ss.channels; c > 0; c--)
+               if (pa_channel_map_init_auto(&map, c, PA_CHANNEL_MAP_ALSA))
+                       break;
+
+       /* Extend if nessary */
+       for (d = c; d < pcm->ss.channels; d++)
+               map.map[d] = PA_CHANNEL_POSITION_AUX0+(d-c);
+
+       map.channels = pcm->ss.channels;
+
        if (io->stream == SND_PCM_STREAM_PLAYBACK)
                pcm->stream =
-                   pa_stream_new(pcm->p->context, "ALSA Playback",
-                                 &pcm->ss, pa_channel_map_init_auto(&map,
-                                                                    pcm->
-                                                                    ss.
-                                                                    channels,
-                                                                    PA_CHANNEL_MAP_ALSA));
+                   pa_stream_new(pcm->p->context, "ALSA Playback", &pcm->ss, &map);
        else
                pcm->stream =
-                   pa_stream_new(pcm->p->context, "ALSA Capture",
-                                 &pcm->ss, pa_channel_map_init_auto(&map,
-                                                                    pcm->
-                                                                    ss.
-                                                                    channels,
-                                                                    PA_CHANNEL_MAP_ALSA));
+                   pa_stream_new(pcm->p->context, "ALSA Capture", &pcm->ss, &map);
 
        if (!pcm->stream) {
                err = -ENOMEM;