Comment 36 for bug 269586

Yep, the enable_msi=1 option fails after resume from hibernate as Mbarak A. Bujra says above.

Also reported more recently here:
  http://www.nabble.com/enable_msi-ignored-on-sleep-restore-tt22296362.html#a22296362

here:
  http://rpm.pbone.net/index.php3/stat/22/idpl/12220340/com/changelog.html

Herton Ronaldo Krzesinski has changelog comments:
  ALSA: hda - Add quirk for another HP dv7
  Enable MSI system wide for systems that need it to function properly (#44855).
  Add MSI quirk list for hda devices, to force enable_msi setting parameter when needed (#44855).

So I guess it's a matter of waiting for Ubuntu to update the kernel...