Warnings on startup

[GitHub issues - opened]

alsa-project/alsa-plugins issue #20 was opened from bramtayl:

I've been trying to get Julia's PortAudio to load alsa-plugins (it's been a process). I thought I might as well see if I can cut down on the warnings on start up (`using PortAudio` from Julia) and some of them I've been able to knock out but some of them not so much:

These ones 

```
ALSA lib pcm.c:2660:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
ALSA lib pcm.c:2660:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
ALSA lib pcm.c:2660:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
```

I got rid of by commenting out lines in my alsa.conf file:

```
# pcm.rear cards.pcm.rear
# pcm.center_lfe cards.pcm.center_lfe
# pcm.side cards.pcm.side
```

This one

```
ALSA lib pcm_route.c:877:(find_matching_chmap) Found no matching channel map
```

I got rid of by commening out:

```
# pcm.surround21 cards.pcm.surround21
# pcm.surround40 cards.pcm.surround40
# pcm.surround41 cards.pcm.surround41
# pcm.surround50 cards.pcm.surround50
# pcm.surround51 cards.pcm.surround51
# pcm.surround71 cards.pcm.surround71
```

I'm not sure if these work arounds are the best solutions...shouldn't alsa be able to tell that my laptop doesn't have surround sound?

This one is expected, I haven't yet figured out how to build jack on Julia's BinaryBuilder:

```
ALSA lib dlmisc.c:339:(snd_dlobj_cache_get0) Cannot open shared library libasound_module_pcm_jack.so (/home/brandon/.julia/artifacts/d587f48a6815c72dec4b083bf297caec7a8e3f4b/lib/alsa-lib/libasound_module_pcm_jack.so: cannot open shared object file: No such file or directory)
```

These ones are a bit confusing; 

```
ALSA lib pcm_oss.c:377:(_snd_pcm_oss_open) Unknown field port
ALSA lib pcm_usb_stream.c:486:(_snd_pcm_usb_stream_open) Invalid type for card
```

Is it possible that `oss/50-oss.conf` and `usb_stream/98-usb-stream.conf` need to get updated?

Issue URL     : https://github.com/alsa-project/alsa-plugins/issues/20
Repository URL: https://github.com/alsa-project/alsa-plugins