MSI K9NGM Series User Manual page 75

Realtek ALC883 Audio
Connector Settings
Click to access connector settings.
Disable front panel jack detection (option)
Jack detection function only works with HD audio front panel.
M ute rear panel output when front headphone plugged in.
Enable auto popup dialogue, when device has been plugged in
Once this item checked, the dialog "Connected device" would not automatically pop
up when device plugged in.
A-13