[Gentoo] How to enable audio

1. Modify the permission of the folder of user (user:group)
   The following action will see output device become “dummy output”
   cd ~
   sudo chown freeman:freeman .* -R
   
2. Modify the file permission which are under /dev/snd like below (permission : 777)
   This action will let output device from “dummy output” to “speak”.
   
   

   happy@localhost /dev/snd $ ls -al
   total 0
   drwxr-xr-x  3 root root      280 Jul  2 01:18 .
   drwxr-xr-x 18 root root     4240 Jul  2 01:18 ..
   drwxrwxrwx  2 root root       80 Jul  2 01:18 by-path
   crwxrwxrwx  1 root audio 116,  6 Jul  2 01:18 controlC0
   crwxrwxrwx  1 root audio 116,  2 Jul  2 01:18 controlC1
   crwxrwxrwx  1 root audio 116, 10 Jul  2 01:18 hwC0D0
   crwxrwxrwx  1 root audio 116,  5 Jul  2 01:18 hwC1D0
   crwxrwxrwx  1 root audio 116,  7 Jul  2 01:34 pcmC0D3p
   crwxrwxrwx  1 root audio 116,  8 Jul  2 01:34 pcmC0D7p
   crwxrwxrwx  1 root audio 116,  9 Jul  2 01:34 pcmC0D8p
   crwxrwxrwx  1 root audio 116,  4 Jul  2 01:34 pcmC1D0c
   crwxrwxrwx  1 root audio 116,  3 Jul  2 01:34 pcmC1D0p
   crwxrwxrwx  1 root audio 116,  1 Jul  2 01:18 seq
   crwxrwxrwx  1 root audio 116, 33 Jul  2 01:18 timer
   

Reference:

• ALSA