XFree86 4.3 improper monitor timing issue - fixed!

[nadmaximus]

You may remember the issue, posted about in a few threads here, regarding improper monitor timings with XFree86 4.3. In my case, this was on my Sunblade 100. In spite of all efforts at creating a valid XF86Config file, it always seemed to result in sync values roughly double what they should be.

After wrestling with it off and on for months, I gave it a nice long rest, and then revisted the issue just now.

From the XFree86 documentation on ATI driver options (http://www.xfree86.org/~dawes/4.3.0/ati.html):

5.17. Option ``ReferenceClock'' ``frequency''

This option is only applicable to non-Intel platforms, where an adapter BIOS is not available to the driver. The option specifies the reference frequency used by the adapter's clock generator. The default is 14.318 MHz, and other typical values are 28.636, or 29.5 MHz.

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The above paragraph clicked with me, so I went and tried a reference clock of 14.318, which had no effect, then I tried 28.236. It worked, also 29.5 in my case produces a valid display. I have done a bit of looking, trying to find what exactly the frequency should be, but the 28.636 MHz seems to work fine.

I added the following to my XF86Config in the device section for the card:

Option "reference_clock" "28.636 MHz"

Finally!
- I am Gatling on the IRC here, because that's what I logged in as first =)