Lindsay -- Free at Last

Lindsay Lohan is out of jail.

Law enforcement sources say Lohan was cooperative in jail. We're told she was very upset.

A law enforcement source at the Santa Monica jail tells TMZ "she did just about everything we asked."

So what didn't Lindsay do? She refused to submit to a PASD -- Preliminary Alcohol Screening Device. That's a chemical test administered in the field to determine blood alcohol levels.

We're told cops did administer a walk-the-line test, and Lindsay flunked.