No sound; Alsa-driver is still broken in Ubuntu 9.04 for HP w/IDT 92HD71B7 chipset

1) Alsa driver doesn't work for ATI RS780 / IDT chip found in my laptop. I believe this chip is common to recent HP DV4, DV5, DV7 models. Affects Ubuntu 8.10, Fedora 10, Ubuntu 9.04 (both LiveCD & upgrade from 8.10)

Workaround:
Go to alsaproject, download alsa-driver & alsa-kmirror. Compile alsa-kmirror first. I used git checkout to pull the source, followed by ./gitconfigure and make install.

Recompile alsa-driver every time the kernel is changed.

IDT supposedly has Linux drivers, but will not provide them to end-users. HP doesn't support Linux on their laptops.

Since alsaproject has fixed this, this is an Ubuntu and Fedora bug.


2) After compiling, mute & volume "smart keys" don't work. Martin Owen pointed out that the keys are actually working, they just aren't doing the right thing. System > Preferences > Keyboard Shortcuts gives us a gui. XF86AudioMute causes a "Volume Mute" action. Too bad the gui is undocumented.
This is also an Ubuntu and Fedora bug, or upstream. Workaround: Systems > Preferences > Sound. Change Default Mixer Tracks to Playback: simultaneous output to HDA ATI SB - STAC ...