GIGABYTE GA-MA78LMT-S2H - Manual (Page 87)

- 87 - Appendix
If your chassis provides an AC'97 front panel audio mod-
ule, to activate the AC'97 functionality, click the tool icon
on the Speaker Configuration tab. On the Connector
Settings dialog box, select the Disable front panel jack
detection check box. Click OK to complete.
Click Device advanced settings on the top right corner
on the Speaker Configuration tab to open the Device
advanced settings dialog box. Select the Mute the rear
output device, when a front headphone plugged in
check box. Click OK to complete.
C. Activating an AC'97 Front Panel Audio Module
D. Muting the Back Panel Audio (For HD Audio Only)