What do you do to keep your top customer loyal? You schmooze a little.

That’s what BlackBerry CEO John Chen has done with his most public customers, the people in the White House.

Chen told Bloomberg News this week that he’s briefed unnamed people about what’s going on in his company “from an IT perspective,” while they let him know “”some of the stuff they would like us to work on.”

The kind of conversation you have with your customers.

During the interview he also said that the Q20 – a BlackBerry 10 device with a physical keyboard plus the classic trackpad missing from the Q10 and Q5, will likely appear in the fall, just before the all-important holiday buying period.

Chen is trying to stabilize BlackBerry, whose promised revival with BlackBerry 10 handsets has been a disappointment to millions of its loyal fans.

We’ll get a partial report card on his efforts — he’s only been on the job since November — Blackberry will release its latest quarterly results March 28.