Hollywood loves its messed-up, tragic rock stars, and a biopic of hippie icon and "white blues" singer Janis Joplin has been in the works for longer than anyone can remember, with everyone from Pink to Amy Adams slated for the lead role.

That it never seems to come together is telling. The ending to Joplin's arc — death by heroin overdose in 1970 at age 27 — provides no redemption, just stone-cold tragedy. Besides, the Joplin story has already been told well, albeit thinly fictionalized, by the movie that made Bette Midler a star — 1979's "The Rose."

In the absence of a biopic, American public broadcaster PBS offers up another Joplin documentary: "Janis: Little Girl Blue," by director Amy J. Berg. While the doc is aimed squarely at PBS' generous baby boomer audience — doing little to contextualize Joplin's significance for a younger generation — it looks beyond the wild-child rock-chick cliche to find different shades of Joplin: the instinctual musician who learned from Odetta records, the loving daughter who regularly penned letters to her parents, the outgoing girl in a boys' world whose childhood insecurities never left her and the woman who struggles with addiction.