With 3.1-rc4 Skype makes very unpleasant noises when playing event sounds or voice. Sometimes a reboot may be able to fix it, but with with 3.0 it always worked fine.

Some new warnings are shown in dmesg for 3.1-rc4 related to alsa:

hda-intel: Invalid position buffer, using LPIB read method instead. hda-intel: Invalid position buffer, using LPIB read method instead. hda-intel: IRQ timing workaround is activated for card #0. Suggest a bigger bdl_pos_adj.

I'm attaching the output of alsa-info utility.