Strange and interesting thing has happened to me recently. I’m a user of Dell D620 laptop, which has Intel’s HDA controller and Sigmatel’s STAC9200 codec. This has always worked perfectly fine, and in my mixer I could see at least two volume controls: Master and PCM. Changing volume using both worked.

Once I’ve upgraded my Linux 3.2 to 3.4, and have noticed that Master volume control is no more. What’s up I thought, but did nothing. Update to 3.5 hasn’t fixed the problem. Okay, it’s time to bisect stuff.