[CentOS] 6.2 Radeon HDMI audio gotcha

I had some trouble (now solved) with the recent upgrade to 6.2.
There was no sound from the DVI/HDMI output and video played back
much too fast.  Booting kernel-2.6.32-131.21.1.el6.x86_64
restored sound and video playback.  The solution is to add
'radeon.audio=1' to the kernel arguments from grub and the new 
kernel also worked.

I'm using CentOS 6 on a media computer with the following graphics
chip:

01:05.0 VGA compatible controller: ATI Technologies Inc RS880 [Radeon
HD 4200]
01:05.1 Audio device: ATI Technologies Inc RS880 HDMI Audio [Radeon HD
4200 Series]

The Linux 3.0 kernel has the audio device disabled by default
because some users were suffering from blank screens.  These
changes were then backported to the Radeon kernel driver for 6.2.
Some searching revealed this as known issue, including Fedora bug
754825 and Ubuntu bug 897008.

I'm reporting this here because I didn't see it mentioned in
either the upstream 6.2 release notes or the CentOS 6.2 release
notes.

Finally, thanks to the CentOS team for another fine release.

Jim