Arch Linux

Description:
I used to be able to use the surround51 device from programs (in particular, Kaffeine with the Xine backend or MPlayer) to play 5.1 audio. However, after I ran "pacman -Syu" on 2008-11-14, any attempt to do that will fail to play any sound, will cause the program to stop responding to input, and will cause the "%CPU" field in "top" for the process to rise to 100. The "pacman -Syu" run updated alsa-lib from 1.0.17a-1 to 1.0.18-1 and kernel26 from 2.6.27.4-1 to 2.6.27.5-1, so I'm not sure which one the problem is in. I ran another "pacman -Syu" just now, which upgraded the kernel to 2.6.27.6-1, and the problem is still present.

Additional info:
* package version(s)
alsa-lib 1.0.18-1
kernel26 2.6.27.6-1
kaffeine 0.8.7-1
mplayer 1.0rc2-7
* config and/or log files etc.
This is the information that alsamixer displays about the sound hardware:
Card: HDA Intel
Chip: Realtek ALC882
The lspci output about the audio hardware is attached.
Also, I noticed that contents of /proc/asound/version are: "Advanced Linux Sound Architecture Driver Version 1.0.17." Is it a problem that alsa-lib has a greater version number than this?

Steps to reproduce:
Run "top", run Kaffeine (using the Xine backend), open the "Settings -> xine Engine Parameters" dialog, set the value for the configuration parameter device.alsa_surround51_device to "plug:surround51:0" if it isn't already (it probably is already set to that, because that's the default), put a DVD with 5.1 audio in the drive, press the "Play DVD" button in Kaffeine, navigate to the part of the DVD content that has 5.1 audio, and watch the CPU utilization that "top" reports for the kaffeine process.