I have this wierd issue with my notebook. Sometimes I have just no sound from integrated speakers but headphones work properly. I have checked that they work in Windows so it seems that there may be some configuration problem.
Worst thing is I had not found deterministic way to reproduce this behaviour. I have finaly gave in as it occured again.
Here is my audio device list:
lspci|grep Audio 00:03.0 Audio device: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor HD Audio Controller (rev 06) 00:1b.0 Audio device: Intel Corporation 8 Series/C220 Series Chipset High Definition Audio Controller (rev 05)
I attach also kernel config and alsa.conf from modprobe. I will post additional info if needed.