As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI OUT CABIN AIR HOT. PACK CONTROL SWITCHED TO MANUAL AND FULL COLD. AT ROTATION CREW REPORTED SMOKE AND HEAT IN CABIN. FLIGHT RETURNED TO ATL FOR AN UNEVENTFUL LANDING. MAINTENANCE FOUND AUTO TEMP CONTROLLER BAD. MANUAL CONTROL WORKS OK. REPLACED TEMP CONTROL. OPERATION CHECKS GOOD.