我有一台 Inspiron 17R SE 7720，安装了 Ubuntu 14.04，我想启用 2.1 音频。
操作系统按原样安装，没有任何变化。但是，我的低音炮不工作。
并且无法使用键盘上的多媒体按钮来改变音量和静音。
我尝试自己解决这个问题，并使用了有关类似问题的所有信息，但没有任何帮助。
以下是一些附加信息：
lspci | grep -i "audio device"
00:1b.0 Audio device: Intel Corporation 7 Series/C210 Series Chipset Family High Definition Audio Controller (rev 04)
cat /proc/asound/card0/codec* | grep Codec
Codec: IDT 92HD91BXX
Codec: Intel PantherPoint HDMI
pulseaudio --dump-conf
### Прочитать из файла конфигурации: /etc/pulse/daemon.conf ###
daemonize = no
fail = yes
high-priority = yes
nice-level = -11
realtime-scheduling = yes
realtime-priority = 5
allow-module-loading = yes
allow-exit = yes
use-pid-file = yes
system-instance = no
local-server-type = user
cpu-limit = no
enable-shm = yes
flat-volumes = no
lock-memory = no
exit-idle-time = 20
scache-idle-time = 20
dl-search-path = /usr/lib/pulse-4.0/modules
default-script-file = /etc/pulse/default.pa
load-default-script-file = yes
log-target = auto
log-level = notice
resample-method = speex-float-1
enable-remixing = yes
enable-lfe-remixing = no
default-sample-format = s16le
default-sample-rate = 44100
alternate-sample-rate = 48000
default-sample-channels = 2
default-channel-map = front-left,front-right
default-fragments = 8
default-fragment-size-msec = 10
enable-deferred-volume = yes
deferred-volume-safety-margin-usec = 1
deferred-volume-extra-delay-usec = 0
shm-size-bytes = 0
log-meta = no
log-time = no
log-backtrace = 0
rlimit-fsize = -1
rlimit-data = -1
rlimit-stack = -1
rlimit-core = -1
rlimit-rss = -1
rlimit-as = -1
rlimit-nproc = -1
rlimit-nofile = 256
rlimit-memlock = -1
rlimit-locks = -1
rlimit-sigpending = -1
rlimit-msgqueue = -1
rlimit-nice = 31
rlimit-rtprio = 9
rlimit-rttime = 1000000