Terrible display flickering after FC5 update today

[Tom Horsley]

On Fri, 27 Oct 2006 13:12:51 -0400
Adam Jackson <ajackson at redhat.com> wrote:

> It shouldn't be doing so anymore, at least in FC6.

Yea, now it won't let you put in a modeline at all, insisting on using
the stuff it calculates itself.

> The other problem is that your card only has a fixed amount of memory 
> bandwidth.  The DAC or TMDS controller has to compete with the rendering 
> engine for access to pixels; if it loses, the frame will just go black. 
>   1920x1080 at 60 Hz is 124 megapixels per second, and at 32bpp that's 
> 500MB/sec.  VRAM is fast but not always that fast.

This worked fine on FC5 with the modeline I manually constructed from
the timing information it printed in the X log file, the same modeline
it claims to be automagically deducing now, but the timings as they get
to the monitor aren't the same as the timings the X log file says the
modeline should generate. Something has changed in the X driver to
screw up the signal it generates from the FC5 days.

I've added this xorg bug (and am about to venture into the world
of radeon driver building to see if I can apply some patches I found
in the bugzillas):

https://bugs.freedesktop.org/show_bug.cgi?id=8790