Looks like they are making progress in porting Linux. No idea if they got HDMI working yet. I also recall reading there is audio distortion.
What's working out of the box:
Graphics, Touchscreen, SD-Card, Power button, Touchpad.
What needs patching:
Wifi (poorly), Sound (with patches), battery monitoring, shutdown, blue-tooth
What's not working:
Camera, Suspend, hibernation, backlight, ambient light sensor, volume keys, screen rotation.
Regarding HD Audio over HDMI. It may be a hardware limitation. From the Z37xx spec sheet for HDMI register setup on Intel's site: