Well, to answer Jim's query ("why do they make movies like this?"), the tragic/romantic jazz player has been a Hollywood trope for a while, going back at least to Kirk Douglas and "Young Man with a Horn." I'm not a trumpet player, but I think I read that Hawke did work on getting the fingering right. As for his singing, since I was never a fan of Baker's singing, Hawke sounded about as good to me! I thought this one was better--not *much* better--than the Miles movie. Hey, at least it didn't have a stupid/goofy chase scene!
And a documentary on Bock might be interesting.
gregmo