Riff Raff -- Drugs? What Drugs? -- Case Dismissed

Riff Raff was just given a gift courtesy of the D.A. in Greensboro, NC ... TMZ has learned his drug case has gone away.

We broke the story ... the rapper was popped back in August when cops saw his car stopped in the middle of a street at 2:30 AM. A search allegedly turned up some weed, drug paraphernalia and an open container of alcohol.

But despite what seemed to be strong evidence, the D.A.'s office ultimately didn't believe they had enough to get a conviction. And, since this is the season for giving, the D.A. gave him a break ... and dismissed the case entirely.