As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT CREW REPORTED SMOKE IN CABIN ORIGINATING APPROXIMATELY MID-CABIN FROM OVERHEAD. MAINTENANCE FOUND CEILING SIDE WALL BALLAST AT ROW 21 DE BURNT. REMOVED AND REPLACED BALLAST PER MAINTENANCE MANUAL. PERFORMED OPERATION 5088. CHECKS OKAY.