While Ubuntu Linux is supported on the HX3XX series platform, in order to enable the on-board Programmable Services Engine (PSE) , the following BIOS update must take place.
Step 1: Enter the Bios and Enable Expert Mode
Step 2: Enable Pin Control Driver GPIO Scheme
Advanced/RC Advanced Menu/PCH-IO Configuration/PinCntrl Driver GPIO Scheme = Enabled
Step 3: (Optional) Re-Disable Expert Mode
Advanced/Expert Mode = Disabled
For further information on HX3xx BIOS and installing Ubuntu, please refer to these support articles: