xserver-xfree86: problem setting resolution with MGA G550

[Lukas Ruf <ruf@rawip.org>]

Dear all,

with latest xserver-xfree86 ( xserver-xfree8 4.2.1-11 ) I would like
to configure the screen resolution to be 1280x1024 for my LCD monitor.
I am using a Matrox MGA G550 (AGP) card.

In /etc/X11/XF86Config-4, I have the following settings.

Section "Screen"
	Identifier	"Default Screen"
	Device		"Generic Video Card"
	Monitor		"Generic Monitor"
	DefaultDepth	24
	SubSection "Display"
		Depth		1
		Modes		"1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
	SubSection "Display"
		Depth		4
		Modes		"1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
	SubSection "Display"
		Depth		8
		Modes		"1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
	SubSection "Display"
		Depth		15
		Modes		"1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
	SubSection "Display"
		Depth		16
		Modes		"1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
	SubSection "Display"
		Depth		24
		Modes		"1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
EndSection

And in /var/log/XFree86.0.log, I get the following, problem-related
messages:

[...]
(==) MGA(0): Using gamma correction (1.0, 1.0, 1.0)
(==) MGA(0): Min pixel clock is 12 MHz
(==) MGA(0): Max pixel clock is 360 MHz
(II) MGA(0): Generic Monitor: Using hsync range of 30.00-60.00 kHz
(II) MGA(0): Generic Monitor: Using vrefresh range of 50.00-75.00 Hz
(II) MGA(0): Clock range:  12.00 to 360.00 MHz
[...]
(II) MGA(0): Not using default mode "1280x1024" (hsync out of range)
[...]
(II) MGA(0): Not using mode "1280x1024" (no mode of this name)
[...]

So, my question is quite simple: how can I get my box to provide an
X-Interface at 1280x1024?  Or what do I have to change to make it
work?

If anyone knows the solution to my problem, I would be happy to get 
any help.

Thanks in advance,

wbr,
Lukas
-- 
Lukas Ruf           | Wanna know anything about raw |
<http://www.lpr.ch> | IP?  <http://www.rawip.org>   |