As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DFW - FLIGHT CREW REPORTED CABIN PRESSURIZATION PROBLEM AT FLIGHT LEVEL 320. AFTER TEN MINUTES CABIN ALT LIGHT ILLUMINATED AND NO INDICATION FROM CONTROLLER THAT IT WENT TO STANDBY. CREW INITIATED DESCENT AND WENT TO MANUAL PRESSURIZATION. ALL OXYGEN MASKS DROPPED DURING DESCENT. LANDED DFW WITHOUT INCIDENT. CHANGED BOTH CABIN PRESSURE CONTROLLERS. SYSTEM GROUND CHECKED NORMAL OPERATION.