Radeon and flat-panel flickering

Russell Shaw rjshaw at netspace.net.au
Wed Apr 18 11:17:20 PDT 2007

Daniel Stone wrote:
> 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.
> http://www.google.com/search?q=vbe+edid
>> 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.)

I would assume that couldn't be the problem, because the noisiness
was with a non-changing desktop.

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