Dina and Michael Lohan HAMBURGER SUMMIT!!!

5/30/2013 9:46 AM PDT

Dina and Michael Lohan -- HAMBURGER SUMMIT!!!


It's like a peace pipe with ketchup -- Dina and Michael Lohan buried the hatchet Wednesday night over burgers ... for the sake of their daughter.

Our spies tell us ... Lindsay Lohan's extremely dysfunctional parents had dinner at the W Hotel in Hollywood, and it seemed like it went beyond concern for their daughter. 

We're told Dina and Michael were laughing a lot and visibly friendly.  We're told they spent time talking about Lindsay and mending the family.

Dina's mood obviously changed a lot in a matter of hours -- earlier in the day at LAX, she sounded a lot less enthusiastic about Michael visiting Lindsay.

As we reported ... Lindsay's treatment at Betty Ford involves family counseling -- something Dina and Michael previously were unwilling to do together.  Lindsay has tried to mend fences, and now it seems that's exactly what's happening.