Comment 10 for bug 138322

I had the exact same problem on my Toshiba A100. I had this problem in Feisty too. I applied the same trick that I used in Feisty to get it working and it worked. Volume works fine now. For the Feisty bug reference: https://bugs.launchpad.net/ubuntu/+source/linux-source-2.6.20/+bug/94373
You'll see my comment.

What I did was:
echo "options snd-hda-intel model=3stack" >> /etc/modprobe.d/alsa-base

and rebooted.

From lspci:
00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 02)
        Subsystem: Toshiba America Info Systems Unknown device ff10
        Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR-
        Latency: 0, Cache Line Size: 64 bytes
        Interrupt: pin A routed to IRQ 22
        Region 0: Memory at f0b40000 (64-bit, non-prefetchable) [size=16K]
        Capabilities: [50] Power Management version 2
                Flags: PMEClk- DSI- D1- D2- AuxCurrent=55mA PME(D0+,D1-,D2-,D3hot+,D3cold+)
                Status: D0 PME-Enable- DSel=0 DScale=0 PME-
        Capabilities: [60] Message Signalled Interrupts: Mask- 64bit+ Queue=0/0 Enable-
                Address: 0000000000000000 Data: 0000
        Capabilities: [70] Express Unknown type IRQ 0
                Device: Supported: MaxPayload 128 bytes, PhantFunc 0, ExtTag-
                Device: Latency L0s <64ns, L1 <1us
                Device: Errors: Correctable- Non-Fatal- Fatal- Unsupported-
                Device: RlxdOrd- ExtTag- PhantFunc- AuxPwr- NoSnoop+
                Device: MaxPayload 128 bytes, MaxReadReq 128 bytes
                Link: Supported Speed unknown, Width x0, ASPM unknown, Port 0
                Link: Latency L0s <64ns, L1 <1us
                Link: ASPM Disabled CommClk- ExtSynch-
                Link: Speed unknown, Width x0