I've just posted the latest experimental version of the OpenSolaris audiohd driver. This driver includes the latest work from the engineers in Beijing, including a widget parser that enables the driver to work on a much larger variety of audio configurations.
As most motherboards these days ship with an audiohd compliant device, this should greatly expand the support for audio on Solaris systems.
The above driver binary also includes suspend/resume support.
Note that this is not the anticipated Open Sound System driver, but rather an extension of the pre-existing Sun driver. It won't work with OSS. However, there is some chance (I've not tested it myself) that this will even work on Solaris 10.
A webrev of the changes should be posted soon.
In the meantime, if you want to give this a whirl, let me know the results. (To test it, just copy the binary objects into /kernel/drv/amd64/ or /kernel/drv and reboot. -- Yes there are ways to do this without a reboot, but the caveats are too many to list here.)
We're interested in any problem reports, as well as notification of hardware configurations where this either did or did not work. Thanks!
[ update 10/13/2008: I've changed the link to the files list so that readers can find the latest version posted up on the site ]