roadgo# cat /dev/sndstat
FreeBSD Audio Driver (newpcm: 64bit 2009061500/amd64)
Installed devices:
pcm0: (play)
pcm1: (play)
pcm2: (play)
pcm3: (play)
pcm4: (play/rec) default
pcm5: (play/rec)
这说明已经成功了
pcm4: (play/rec) default
第一行到第四行是显卡中声音内容。
此时还没有声音发出来（其实是有的，只不过是要耳机才能听到）
vi /etc/sysctl.conf
增加hw.snd.default_unit=5
roadgo# cat /dev/sndstat
FreeBSD Audio Driver (newpcm: 64bit 2009061500/amd64)
Installed devices:
pcm0: (play)
pcm1: (play)
pcm2: (play)
pcm3: (play)
pcm4: (play/rec)
pcm5: (play/rec) default
笔记本的喇叭正常发出声音。