Comment # 20 on bug 76564 from jeroen

(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?