https://bugs.freedesktop.org/show_bug.cgi?id=69675
--- Comment #8 from Andy Furniss adf.lists@gmail.com --- (In reply to comment #2)
From IRC: <Anssi> agd5f: you might've seen already, but the 23.976 Hz pixel clock 74175.824175 is rounded up to 74176 in Ville's commit
FWIW I guess he did this because 74.176 appears in CEA D for 23.976, there isn't anything for 23.976 in E.