[Bug 54381] [drm:radeon_atom_pick_pll] *ERROR* unable to allocate a PPLL

https://bugzilla.kernel.org/show_bug.cgi?id=54381

--- Comment #5 from Alex Deucher alexdeucher@gmail.com 2013-02-25 20:16:03 --- (In reply to comment #4)

As per xrandr (projector NOT connected): DVI-0: 1280x1024 60.0*+ DVI-1: 1920x1200 60.0*+ HDMI-0: 1920x1200 60.0*+

The output DVI-1 with the projector connected: 1920x1080 60.0*+

Worked fine until 3.7.0.

Can you dump the full modelines with pixel clocks (xrandr --verbose)? I suspect the pixel clocks for 1920x1200 and 1920x1080 modes are close enough that one of the monitors was able to tolerate a slightly incorrect pixel clock. Some monitors are more tolerant than others. Projectors tend to be since they usually support a wide range of signals from various inputs.