I have just built a computer and installed 14.04 (trusty) from USB. When I was trying Ubuntu running off the USB the audio was working, as it was after I installed Ubuntu.
Then I changed my graphics to my graphics card -Gigabyte nvidia 960 4GB DDR5, dual DVI-I/D + Display port + HDMI, and the audio stopped working. The graphics are working fine.
I believe the problem is that the audio is now being routed through my graphics card to the HDMI, but I am unable to test this as I have no HDMI devices.
I have checked this question and this question, but have ensured that my Intel Audio is set to enabled in the BIOS. I have also tried following the fix suggested here and here, but changing this conf file has not given me any fix.
I think that Ubuntu is still recognising the motherboard audio, but is not allowing it to be selected any more.
From lshw:
...
*-multimedia
description: Audio device
product: NVIDIA Corporation
vendor: NVIDIA Corporation
physical id: 0.1
bus info: pci@0000:01:00.1
version: a1
width: 32 bits
clock: 33MHz
capabilities: pm msi pciexpress bus_master cap_list
configuration: driver=snd_hda_intel latency=0
resources: irq:17 memory:df080000-df083fff
...
*-multimedia
description: Audio device
product: Intel Corporation
vendor: Intel Corporation
physical id: 1f.3
bus info: pci@0000:00:1f.3
version: 31
width: 64 bits
clock: 33MHz
capabilities: pm msi cap_list
configuration: driver=snd_hda_intel latency=32
resources: irq:16 memory:df220000-df223fff memory:df200000-df20ffff
...
And from aplay -l
**** List of PLAYBACK Hardware Devices ****
card 1: NVidia [HDA NVidia], device 3: HDMI 0 [HDMI 0]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 7: HDMI 1 [HDMI 1]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 8: HDMI 2 [HDMI 2]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 9: HDMI 3 [HDMI 3]
Subdevices: 1/1
Subdevice #0: subdevice #0
Anyone got any pointers? Feel free to ask any further questions.