This is copied from the email sent by email@example.com to android-x86 discussion group
With some poking around, I made the AC97 virtualbox audio device work
with android-x86, here's how:
1. Config kernel, select all PCI audio devices (sorry I don't know which
one is the right one, from lsmod output, it should be snd_intel8x0).
2. Patch external/alsa-utils/Android.mk with the attached patch, so that
the /system/usr/share/alsa/init/ folder will be populated with those
files from external/alsa-utils/alsactl/init/
3. Do a clean full build. (Or, make sure that those changes are
effective in the final iso image, i.e., the .ko modues and the alsa/init
files should show up in the system).
The following modules are loaded on my virtualbox:
snd_pcsp 8948 0 - Live 0xf8938000
snd_intel8x0 27888 3 - Live 0xf8918000
snd_ac97_codec 94676 1 snd_intel8x0, Live 0xf88e3000
ac97_bus 1300 1 snd_ac97_codec, Live 0xf88bd000
snd_pcm 65144 4 snd_pcsp,snd_intel8x0,snd_ac97_codec, Live 0xf8889000
snd_timer 18940 1 snd_pcm, Live 0xf8865000
snd 50660 10 snd_pcsp,snd_intel8x0,snd_ac97_codec,snd_pcm,snd_timer, Live 0xf884a000
snd_page_alloc 8028 2 snd_intel8x0,snd_pcm, Live 0xf8831000
4. After the android system boot, run this command
alsa_ctl restore 0 -f /sdcard/1.txt
The 1.txt file is also attached, I think mainly it just unmute the audio
volume. You should adb push it onto the sdcard. Or better, come up with
a way to make it run automatically during boot. Also, the sb16 won't
work with my eclair-x86; there is just no sound. I doubt it's because
the same reason (i.e., sound is muted).
2010-07 Updated: The ICH AC97 support has been added to froyo-x86 branch.