Dear Takashi,

I have a regression here on 3.1-rc9+ causing the sound "going too fast" 
with hda. Reverting 798cb7e897210 (ALSA: hda - Fix a regression of the 
position-buffer check) fixes this regression for me.

Of course, as this commit is itself a regression fix, my goat feeling is 
that it's not going to be possible to directly revert it. Attached if 
the output of alsa-info.sh (on the fixed kernel). Please let me know if 
I can provide you any additional information or test any patch.

Cheers,
Éric