1.在/etc/modprobe.d/alsa-base.conf文件中加入下面这行options snd-hda-intel model=5stack enable=1 index=0（主要就是修改这些参数）
2. sudo alsa force-reload 下文可以不看了。。。
可能是硬盘安装的缘故，这次安装的ubuntu9.04总是没有声音，只是沙沙响，偶尔打开音乐播放器时有声音，但是渐渐就没有了，然后再也听不见了。今天按照https://help.ubuntu.com/community/SoundTroubleshooting里面的方法，只改了一行。
Is the system recognizing your sound card?
Open a terminal window, and type "aplay -l". Your output should look something like this:
**** List of PLAYBACK Hardware Devices ****
card 0: Intel [HDA Intel], device 0: ALC861VD Analog [ALC861VD Analog]
Subdevices: 0/1
Subdevice #0: subdevice #0
If you see aplay: device_list:221: no soundcard found..., Ubuntu is not recognizing your sound card for playback. Check that you have the proper modules installed.
Do you have the sound modules installed?
Open a terminal window, and type "find /lib/modules/`uname -r` | grep snd".You should see a whole list of items come up. If you don't, it meansthat the upgrade process missed installing the kernel modules forsound. To fix this, type this at the command line:
sudo aptitude install linux-ubuntu-modules-`uname -r` linux-generic
After installing the modules, you will need to reboot.
If the modules are already installed, check to see whether your hardware is recognizing the sound card as installed
Is the sound card physically installed and recognized by your hardware?
Open a terminal window, and type "lspci -v | less".This will check your computer's motherboard, and attempt to list outall devices that it's recognized as installed. There is probably a lotof things listed, but the one you're looking for will be labeled "Audiodevice". Mine is listed below:
00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 02)
Subsystem: Toshiba America Info Systems Device ff01
Flags: bus master, fast devsel, latency 0, IRQ 22
Memory at dc440000 (64-bit, non-prefetchable) [size=16K]
Capabilities: <access denied>
Kernel driver in use: HDA Intel
Kernel modules: snd-hda-intel
Most users have a "built in" sound card for theircomputer on the motherboard. If yours is built in, and isn't showing upin this step, then you probably need to enable it in your BIOS. Whenyou first boot, or reboot your computer, there's usually a key sequencetelling you how to enter the BIOS Configuration Screen. You'll need tosort through your BIOS and enable the built in sound card.
If you are not using a built in sound card, and thisstep does not show your audio card, the card may be seated incorrectlyon your motherboard, or may be bad or otherwise incompatible with yourmotherboard. You will probably want to test the card in anothercomputer to see if it works there.
以上都是为了验证性质的，下面说的是上面都正常的情况下的解决步骤。
Is ALSA using the correct model?
If you are experiencing problems with your soundcard after upgrading to Ubuntu 9.04, it might be because ALSA is usingthe wrong model for your chipset.
To figure out your chipset you can run this command:
wget -O alsa-info.sh http://alsa-project.org/alsa-info.sh && bash ./alsa-info.sh
执行完这条指令后，会把系统信息保存在/temp/alsa-info.txt文件中，下面的设置需要依照里面的信息。
This will provide you with a URL to a webpage withlots of information about your sound setup. Open it up, and keep itopen; you'll need it as a reference.
You can take a look at this webpage as a reference.
Now you need to figure out what models are supportedby your soundcard. This part is a bit backwards, you have to browse theALSA git repository.
The repository is located at http://git.alsa-project.org/?p=alsa-kmirror.git, so open up this URL.
If you look at the webpage with information about your soundsetup, you'll notice it has a section like this:
!!ALSA Version
!!------------
Driver version: 1.0.18
Library version: 1.0.18
Utilities version: 1.0.18
Notice the driver version. This is the version youshould be navigating to in the git repository. If you look at the'tags' section there's a tag called v1.0.18, which is the one we want.
When I navigated into this tag repository, I also had to click the tree link on the top of the page to get a directory listing.
Click the Documnetation directory, and then click ALSA-Configuration.txt.
Remember these links are for the v1.0.18 driver version only, you need to find the appropriate ALSA-Configuration.txt for your driver version.
Now you need to figure out what module is loaded by ALSA on your machine. The webpage with all the information about your system comes to the rescue again:
!!Loaded ALSA modules
!!-------------------
snd_hda_intel
You might have to do a bit of digging to find your module in the ALSA-Configuration.txt file. For my module, it is in the section called:
Module snd-hda-intel
Now I have to figured out what Codec my soundcard uses. This is also on the webpage with my sound configuration.
It has a section that looks like this:
!!HDA-Intel Codec information
!!---------------------------
--startcollapse--
Codec: SigmaTel STAC9227
Now take a look at ALSA-Configuration.txt again, and you will find a section that looks like this, which matches up with my soundcards codec:
STAC9227/9228/9229/927x
ref Reference board
3stack D965 3stack
5stack D965 5stack + SPDIF
dell-3stack Dell Dimension E520
dell-bios Fixes with Dell BIOS setup
A stack is the same as a jack plug in your soundcard.
By inspecting your computer you have to figure outhow many jacks（插座） you have on your soundcard. I have six jacks in theback and two in the front of my computer, so I chose the 5stack model configuration.
So armed with this knowledge, it's about time to start configuring your system.
This is the steps that were necessary to get a Dell Dimension E520 with Intel HDA and SigmaTel STAC9227 Codec to work after upgrading to Ubuntu 9.04:
sudo nano /etc/modprobe.d/alsa-base.conf
This part will depend on your soundcard, it consists of the module name (snd-hda-intel) and the model I found in ALSA-Configuration.txt, 5stack:
options snd-hda-intel model=5stack
And finally:
sudo alsa force-reload