* matroxfb - wrong PLL calculation for Mystique and Mystique 220
@ 2010-08-06 15:35 Ondrej Zary
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From: Ondrej Zary @ 2010-08-06 15:35 UTC (permalink / raw)
To: linux-fbdev
Hello,
there is a long-standing problem in matroxfb (and also with xf86-video-mga)
with PLL values calculation. It results in "wavy" vertical lines at least on
Mystique and Mystique 220, especially where dotted horizontal lines are
displayed.
On non-220 Mystique in 1024x768@85Hz, matroxfb calculates:
m=0x0f, n=0x69, p=0x00 (producing wavy vertical lines)
Windows driver calculates:
m=0x03, n=0x34, p=0x01 (producing straight vertical lines)
The resulting f_vco from windows values is 189713.5, which is above max_freq
for this card. So it looks like the assumption that f_vco must be less
or equal to max_freq is wrong. Could someone with access to MGA1064/1164
documentation look into this?
xf86-video-mga bug (with photos of the screen):
http://bugs.xfree86.org/show_bug.cgi?id\x1314
--
Ondrej Zary
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2010-08-06 15:35 matroxfb - wrong PLL calculation for Mystique and Mystique 220 Ondrej Zary
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