Yamaha chipset on Sony VAIO NV505 laptop. Sndconfig correctly identified the chipset, but the driver hung trying to play a sound. After that, apmd would hang. Only way out is to start linux single, then hand-edit modules.conf and sysconfig/soundcard. This isn't all, because shutdown is sometimes not clean. This is similar to #18026, but less severe and a different driver/chipset.
Patch in 18026 is in sndconfig-0.60-1; your problem is almost certainly solved by using the native ymfpci driver which is in the 2.2.18 and 2.4.0 kernel (the 2.4.0 kernel is currently in rawhide.)