As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOST PRESSURIZATION AT FL 310 BOTH AC PACKS IN AUTO. BOTH 1 AND 2 AUTO PRESSURE CONTROLLERS SHOWED "INOP" ANNUNCIATION. PERFORMED AUTO PRESS CONTROLLER BITE. FOUND BOTH CONTROLLERS FAULTED. RESET CONTROLLERS. AIRCRAFT WAS RETURNED TO SERVICE.