Helped a friend get Debian Testing (Wheezy) set up on his laptop and all appears to be working fine, except that Alsa is not outputting any audio.
lspci (with grep audio) outputs the following details about the available sound devices
00:01.1 Audio device: Advanced Micro Devices [AMD] nee ATI BeaverCreek HDMI Audio [Radeon HD 6500D and 6400G-6600G seres]
00:14.2 Audio device: Advanced Micro Devices [AMD] FCH Azalia Controller (rev 01)
And when trying to play one of the Alsa audio samples with aplay, it outputs:
ALSA lib pcm_dmix.c:1018:(snd_pcm_dmix_open) unable to open slave
aplay: main:682: audio open error: No such file or directory
In the alsa mixer there are two devices, one of which has only a single switch in the xfce-mixer but no controls, while the second has various controls - all of which are unmuted and at full volume, but still no sound is being produced