[alsa-devel] [ALC668]: Asus N751JK - surround 21 and surround40 pulseaudio bug

[Raymond Yau]

>
> Alsa-info patched kernel:
http://www.alsa-project.org/db/?f=cd23a3f0bb72e38d73224620e3e8ab57a73aa441
>
> Chmap results:
>
> Type = FIXED, Channels = 2
>   FL FR
> Type = FIXED, Channels = 4
>   FL FR NA LFE
>
> When unplugging the subwoofer, then chmap gives this and stays like this.
>
> Cannot open PCM stream hw:1 for PLAYBACK
>
> [Pavucontrol] -> [Configuration] -> [Built-in Audio] gives
>
> Analog Stereo Duplex
> Analog Stereo Output
> Analog Surround 2.1 Output + Analog Stereo Input
> Analog Surround 2.1 Output
> Analog Surround 4.0 Output + Analog Stereo Input
> Analog Surround 4.0 Output
> Analog Stereo Input
> Off

Seem pulseaudio bug since your laptop does not have surround40 chmap

It is not clear how pulseaudio's 21 channel-map match with alsa's 2.1 chmap

http://cgit.freedesktop.org/pulseaudio/pulseaudio/tree/src/modules/alsa/mixer/profile-sets/default.conf

[Mapping analog-surround-21]
device-strings = surround21:%f
channel-map = front-left,front-right,lfe
paths-output = analog-output analog-output-lineout analog-output-speaker
priority = 8
direction = output

[Mapping analog-surround-40]
device-strings = surround40:%f
channel-map = front-left,front-right,rear-left,rear-right
paths-output = analog-output analog-output-lineout analog-output-speaker
priority = 7
direction = output
>
> Pulseaudio verbose log while plugging in the subwoofer:
http://pastebin.com/Ya5u1qz6

https://bugs.freedesktop.org/enter_bug.cgi?product=PulseAudio