Comment 8 for bug 149622

I have a similar problem, though it may warrant a separate bug report.

Only the PCM control has any effect on the volume.

Additionally, my desktop computer (Dell Optiplex GX620) has a built-in speaker and the headphone socket. Both play sound when I run speaker-test, though interestingly in the GNOME Sound Preferences dialogue if I test playback I get different results with different device choices. So "Intel ICH7 - IEC958" doesn't produce any sound with either the built in speaker or the headphones. "Intel ICH7", "ALSA", "OSS" and "Autodetect" produce sound for both simultaneously (so headphones don't stop the internal speaker sound).

Some relevant output:

$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: ICH7 [Intel ICH7], device 0: Intel ICH [Intel ICH7]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: ICH7 [Intel ICH7], device 4: Intel ICH - IEC958 [Intel ICH7 - IEC958]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

$ lspci -v
00:1e.2 Multimedia audio controller: Intel Corporation 82801G (ICH7 Family) AC'97 Audio Controller (rev 01)
        Subsystem: Dell Unknown device 01ad
        Flags: bus master, medium devsel, latency 0, IRQ 21
        I/O ports at ec00 [size=256]
        I/O ports at e8c0 [size=64]
        Memory at febffa00 (32-bit, non-prefetchable) [size=512]
        Memory at febff900 (32-bit, non-prefetchable) [size=256]
        Capabilities: <access denied>