https://bugs.freedesktop.org/show_bug.cgi?id=76564
--- Comment #20 from jeroen jeroenk61@hotmail.com --- (In reply to comment #19)
(In reply to comment #16)
(In reply to comment #15)
I got the results with fglrx: PPLL1@50Hz: fb=23.7 ref=2 post=6 PPLL1@23.976Hz: fb=23.7 ref=2 post=12
PPLL2 does seem to be used as it does not change. PPLL1 has different values than with the radeon OSS driver. What does this mean?
(100Mhz * 23.7) / (2 * 6) = 197.5Mhz
(100Mhz * 23.7) / (2 * 12) = 98.75Mhz
Maybe fglrx is using different modelines with a different display clock? Can you print what modes are being used with fglrx and radeon? E.g., xrandr --verbose.
I attached both xrandr outputs.
I also noticed that for fgrlx the PLL values are the same for 50Hz,60Hz and 59.94Hz output.
When I look at the xrandr output I wonder if the reference frequency is not 75MHz for fgrlx? Can the reference even change is this not fixed by the hardware?