[Bug 35098] Headphone Jack doesn't disable speakers

[Jer]

Public bug reported:
https://launchpad.net/malone/bugs/35098

Affects: linux-source-2.6.12 linux-image-2.6.12-10-686 (Ubuntu)
       Severity: Normal
       Priority: (none set)
         Status: Unconfirmed

Description:
I'm using the alsa snd-hda-intel kernel module for sound.  It works fine
with one minor exception;

When the headphone jack is used, sound comes out both the system
speakers AND the headphones.  The system speaker output isn't muted.
Further, there is no option in the mixer to enable/disable or volume
control the headphone output.

The system is a Dell Inspiron B120 laptop with a stac92xx codec chip.

The following is the output from lspci

0000:00:00.0 Host bridge: Intel Corp. Mobile Memory Controller Hub (rev 03)
0000:00:02.0 VGA compatible controller: Intel Corp. Mobile Graphics Controller (rev 03)
0000:00:02.1 Display controller: Intel Corp. Mobile Graphics Controller (rev 03)
0000:00:1b.0 0403: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) High Definition Audio Controller (rev 03)
0000:00:1c.0 PCI bridge: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) PCI Express Port 1 (rev 03)
0000:00:1c.3 PCI bridge: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) PCI Express Port 4 (rev 03)
0000:00:1d.0 USB Controller: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #1 (rev 03)
0000:00:1d.1 USB Controller: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #2 (rev 03)
0000:00:1d.2 USB Controller: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #3 (rev 03)
0000:00:1d.3 USB Controller: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #4 (rev 03)
0000:00:1d.7 USB Controller: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB2 EHCI Controller (rev 03)
0000:00:1e.0 PCI bridge: Intel Corp. 82801 PCI Bridge (rev d3)
0000:00:1f.0 ISA bridge: Intel Corp. 82801FBM (ICH6M) LPC Interface Bridge (rev 03)
0000:00:1f.1 IDE interface: Intel Corp. 82801FB/FBM/FR/FW/FRW (ICH6 Family) IDE Controller (rev 03)
0000:02:00.0 Ethernet controller: Broadcom Corporation BCM4401-B0 100Base-TX (rev 02)
0000:02:03.0 Network controller: Broadcom Corporation: Unknown device 4318 (rev 02)