Linux sound setting(CMI8738)

Sound Card: C-Media CMI8738
OS: Ubuntu Linux 9.04

When running the browser(firefox), the music player(totem) have no sound; on the other hand, when running the music player, the flashplayer in the browser(ex. YouTube) have no sound.

Only one will work at a time.

solution:

change the sound properties(gnome-sound-properties) all to "ALSA (Advanced Linux Sound Architecture)" not those "C-Media CMI8738 ...." and I set "default mixer channel" as "C-Media CMI8738(Alsa mixer)".