I run unity 12.04 crouton precise on my Toshiba and have no audio output
listed in the audio settings. No issue with updating crouton.

crouton: version 1-20141231011135~master:992afe3e
release: precise
architecture: amd64
targets: unity
host: version 6310.68.0 (Official Build) stable-channel leon

System Volume (0-100): 100
Capture Gain (-17.25 - 30.00): 20.00dB
Output Devices:
ID Name
6 HDA Intel PCH: ALC283 Analog:1,0
5 HDA Intel MID: HDMI 2:0,8
4 HDA Intel MID: HDMI 1:0,7
3 HDA Intel MID: HDMI 0:0,3
Output Nodes:
ID Vol Plugged L/R swapped Time Type Name
6:0 100 no no 0 HEADPHONE Headphone
6:1 20 yes no 1420462112 INTERNAL_SPEAKER*Speaker
5:0 100 no no 0 HDMI HDMI/DP,pcm=8 Jack
4:0 100 no no 0 HDMI HDMI/DP,pcm=7 Jack
3:0 100 no no 0 HDMI HDMI/DP,pcm=3 Jack
3:1 100 no no 0 HDMI HDMI
Input Devices:
ID Name
7 HDA Intel PCH: ALC283 Analog:1,0
Input Nodes:
ID Gain Plugged L/R swapped Time Type Name
7:0 0 no no 0 MIC Mic Jack
7:1 0 yes no 1420462112 INTERNAL_MIC *Internal Mic
Selected Output Node: 6:1
Selected Input Node: 7:1
Attached clients:
ID pid uid
7 11184 1000
18 11184 1000
21 28703 1000
22 28703 1000
Num active streams: 0
Last audio active time: 843, 776948125

I have never used the distro but could it be missing the firmware? I know with the more conscientious distros (like Fedora and Debian) they choose not to include any proprietary firmware because doing so would open them up to legal problems. Or the device simply may not work very well with the 64-bit kernel, but may work fine with the 32-bit kernel. Just offering some background to help you begin your search for a solution. Hope this helps.

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