[SWLUG] Screen resolution problems.

[Justin Mitchell]

On Fri, 2009-06-05 at 13:55 +0100, Davage, Marcus wrote:
> I reinstalled fedora 10 with the KVM switch removed, and lo and
> behold, it picked up the 1024x768 screen res!
> 
> Plug the KVM switch in and reboot, and wallop, back to 800x600.

the KVM is screwing up the EDID info query

> There is no /etc/Xorg.conf file.

its /etc/X11/xorg.conf on f10

>  
> 
> Here’s some output from the log…
> 
[snip]

> (EE) R128(0): No DFP detected
> 
> (II) R128(0): <default monitor>: Using default hsync range of
> 31.50-37.90 kHz
> 
> (II) R128(0): <default monitor>: Using default vrefresh range of
> 50.00-70.00 Hz
> 
> (WW) R128(0): Unable to estimate virtual size
> 
> (II) R128(0): Clock range:  12.50 to 400.00 MHz
> 
> (II) R128(0): Not using default mode "640x350" (vrefresh out of range)
> 
> (II) R128(0): Not using default mode "320x175" (vrefresh out of range)
> 

> <snip>

> (II) R128(0): Not using default mode "2048x1536" (hsync out of range)
> 
> (II) R128(0): Not using default mode "1024x768" (hsync out of range)


well theres the reason, it couldnt ask your monitor what it supports so
it took a (really conservative and safe) guess, and lo and behold all
your nice resolutions vanish.


so to fix this you need to write/fix the HorizSync and VertRefresh
numbers in the Monitor section of your xorg.conf file.

you can either find the correct ranges in the monitors manual (google
may help)  or plug it back in without the KVM and see if it reports the
values in the log.


example from my auto detected config:

Section "Monitor"
    # HorizSync source: edid, VertRefresh source: edid
	Identifier   "Monitor0"
	VendorName   "Unknown"
	ModelName    "SEG RM170"
	HorizSync    30.0 - 80.0
	VertRefresh  58.0 - 75.0
	Option	    "DPMS"
EndSection