OK, I'm the farthest thing from a Linux guru, but I'll be glad to share what works for me.
First, I'm running the Intel HDA system, which is integrated on my Intel D975XBX motherboard. The chip is a STAC 92xx.
Second, I am using the ALSA sound system, not OSS. So, first I'll show you what the output of lspci on my system looks like:
dabl@feisty:~$ lspci 00:00.0 Host bridge: Intel Corporation 82975X Memory Controller Hub 00:01.0 PCI bridge: Intel Corporation 82975X PCI Express Root Port 00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 01) 00:1c.0 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 1 (rev 01) 00:1c.4 PCI bridge: Intel Corporation 82801GR/GH/GHM (ICH7 Family) PCI Express Port 5 (rev 01) 00:1c.5 PCI bridge: Intel Corporation 82801GR/GH/GHM (ICH7 Family) PCI Express Port 6 (rev 01) 00:1d.0 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #1 (rev 01) 00:1d.1 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #2 (rev 01) 00:1d.2 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #3 (rev 01) 00:1d.3 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #4 (rev 01) 00:1d.7 USB Controller: Intel Corporation 82801G (ICH7 Family) USB2 EHCI Controller (rev 01) 00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev e1) 00:1f.0 ISA bridge: Intel Corporation 82801GH (ICH7DH) LPC Interface Bridge (rev 01) 00:1f.1 IDE interface: Intel Corporation 82801G (ICH7 Family) IDE Controller (rev 01) 00:1f.2 IDE interface: Intel Corporation 82801GB/GR/GH (ICH7 Family) Serial ATA Storage Controller IDE (rev 01) 00:1f.3 SMBus: Intel Corporation 82801G (ICH7 Family) SMBus Controller (rev 01) 01:00.0 VGA compatible controller: nVidia Corporation GeForce 7900 GS (rev a1) 04:00.0 Ethernet controller: Intel Corporation 82573L Gigabit Ethernet Controller 05:04.0 FireWire (IEEE 1394): Texas Instruments TSB43AB23 IEEE-1394a-2000 Controller (PHY/Link) 05:05.0 RAID bus controller: Silicon Image, Inc. SiI 3114 [SATALink/SATARaid] Serial ATA Controller (rev 02)
and next I'll list the packages that I have installed:
alsa-base alsa-utils alsa-tools alsamixergui alsaplayer-alsa alsaplayer-common alsaplayer-daemon alsaplayer-gtk alsaplayer-jack alsaplayer-oss
and finally I'll post a screenshot of the settings for the input -- sorry this is kmix from Kubuntu, but it's a similar deal for the mixer in Ubuntu (right-click the speaker icon in the upper right corner, choose "open volume control").