As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH - FLT 3793 - PILOT REPORTED DURING CLIMB, THERE WAS SMOKE IN CABIN. THE AIRCRAFT RETURNED AND LANDED TO IAH WITHOUT INCIDENT. MAINTENANCE FOUND THE RIGHT RAM AIR VALVE BROKEN AND THE AIRCRAFT WAS DISPATCHED UNDER MEL 21-51-1C. TO CLEAR THE DISCREPANCY, MAINTENANCE REMOVED AND REPLACED THE RIGHT RAM AIR DUCT ASSEMBLY, AND THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE. (X)