Comment 4 for bug 479375

Hi Alexander and thanks for the effort of trying to trace this bug down! Some thoughts:

* You have these "unusual" lines in dmesg:
hda_intel: probe_mask set to 0x1 for device 17aa:20ac
hda-intel: azx_get_response timeout, switching to polling mode: last cmd=0x012f0c00

According to http://www.kernel.org/pub/linux/kernel/people/tiwai/docs/HD-Audio.html , the latter is just a warning but I think it could be related to what you're experiencing. Read the section about Codec-Probing Problem.

* Another monitor to check could be latencytop (sudo apt-get install latencytop), which logs kernel activities.