As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LGA INFLIGHT - AT 15000 FEET CAPTAINS PRIMARY FLIGHT DISPLAY WENT BLANK AND SMOKE STARTED COMING INTO COCKPIT. TURNED OFF PRIMARY FLIGHT DISPLAY AND ELECTRIC SMOKE FUMES CONTINUED. RETURNED TO LGA AND LANDED WITHOUT INCIDENT. REPLACED ELECTRONIC FLIGHT INSTRUMENT SYSTEM UNIT. SYSTEM GROUND CHECKED NORMAL OPERATION.