Radeon and flat-panel flickering

Daniel Stone daniel at fooishbar.org
Wed Apr 18 10:32:55 PDT 2007

On Thu, Apr 19, 2007 at 03:12:00AM +1000, Russell Shaw wrote:
> IIRC, the pc bios sets the graphic card into a common vga mode,
> so how does the graphic card know the monitor parameters?
> Something must be reading the monitor edid on bootup, because
> booting with the CRT made the noisiness go away.


> It seems like a signal timing problem at the crtc output. How
> could it be a DisplayPriority "display buffer underflow" if the
> video signal is just a readout of non-changing memory contents?

Well, if you look at what DisplayPriority does ...

Essentially, it specifies that if there is contention in the memory bus
between the GPU (wanting to write, say, glxgears at nine hojillion FPS),
and the DAC (wanting to scan out), that the desired behaviour is ...

(Answer left as an exercise for the reader.)

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