Bug#512273: xorg: Macintosh Blue&White G3 w/ ATI 3D Rage Pro - monitor complains "out of range"
2009/1/19 Rick Thomas <email@example.com>:
> When X starts up the monitor displays a message "out of range" indicating
> that the
> computer is feeding it stuff it can't handle. (This message is coming from
> monitor, itself -- not the X software). The image on the monitor shimmers
> jumps and looks like snow in a high wind.
This sounds worse than my problem, but it may depend on the same
source, i.e. something probably programmed in by Open Firmware into
the chip's registers.
Looking at file atidsp.c, function ATIDSPPreInit, near its beginning,
you can see:
/* Retrieve XCLK settings */
IOValue = ATIMach64GetPLLReg(PLL_XCLK_CNTL);
pATI->XCLKPostDivider = GetBits(IOValue, PLL_XCLK_SRC_SEL);
pATI->XCLKReferenceDivider = 1;
What I did, I changed the line setting pATI->XCLKPostDivider to:
pATI->XCLKPostDivider = 1;
and the problem with my display image disappeared.
Now, I can't say that 1 will be the correct value in your case, or
even promise that it won't make things worse. And I must add that I
made my change in similar code in Linux kernel's
drivers/video/aty/mach64_ct.c on an Oldworld Mac.
The result from this change will be that some values calculated by the
code and later written into the chip's registers become different.
I found some useful tools for peeking and poking the chip, f.ex.
atydump, I will put a copy available here: