down the LCD panel rabbit hole

brian fedora at
Tue Aug 11 04:27:43 UTC 2009

On 08/10/2009 08:06 PM, brian wrote:
> On 08/10/2009 08:11 PM, Frank Cox wrote:
>> On Mon, 10 Aug 2009 19:38:20 -0400
>> brian wrote:
>>> SIS 661/741/760 PCI/AGP or 662/761Gx PCIE VGA
> Maybe I should clarify. As I mentioned in the original post, I've
> already found that site but am having a lot of trouble understanding
> much of it.

But thanks (a lot!) for the nudge, all the same. After re-reading 
*carefully* that Sis driver site, and spending awhile poring over the 
xorg.conf man page, the clue train finally arrived. It wasn't without 
some issues, still, though, as I screwed up and had to go into rescue 
mode a couple of times until I had the conf file squared away.

So, for anyone else who has similar trouble ...

The above-mentioned site suggests using a "blitter" mode for certain 
chipsets if the system is using shared video memory. Indeed, Xorg.0.log 
had a comment along those lines. This can be set as an option in xorg.conf.

The panel's user guide specifies a horiz. freq. of 55.62KHz, vert. freq. 
of 49.92 Hz, and a sync polarity -H/+V for 1920 x 1080 resolution. So, I 
edited xorg.conf to include:

Section "Monitor"

#	UseModes     "1920x1080-55.62"
	Identifier   "Monitor0"
	VendorName   "DEL"
	ModelName    "DELL S2209W"
	HorizSync    30.0 - 83.0
	VertRefresh  50.0 - 76.0
	ModeLine     "1920x1080-55.62" 159.0 1920 2040 2240 2560 1080 1083 1088 
1118 -hsync +vsync
	Option	    "DPMS"

Section "Device"
	Identifier  "Videocard0"
	Driver      "sis"
	Option	    "XvDefaultAdaptor" "Blitter"

Section "Screen"
	Identifier "Screen0"
	Device     "Videocard0"
	Monitor    "Monitor0"
	DefaultDepth     24
	SubSection "Display"

#		Modes "1920x1080-55.62"
		Viewport   0 0
		Depth     24

(The ModeLine was actually a Mode block--not a Mode Section!--that seems 
to have been rewritten but whatever)

As I said, I was forced into rescue mode after a failed restart. I 
checked /var/log/Xorg.0.log which told me that there was a:

Undefined Modes Section "1920x1080-55.62" referenced by Monitor "Screen0"

I commented out the Modes line in Display Subsection of the Screen 
section (the manual says that it's optional) and rebooted. Same problem. 
I went into rescue mode again and saw the same error. At this point, I 
realised that the trouble was actually with the UseModes line of the 
Monitor section. The manual clearly states that this refers to a Mode 
section, not a Mode block ("multi-line entry"). I didn't have any Mode 

Can you tell it's been a long day? Would you believe that I do a lot of 
proofreading for a living? I kid you not.

Anyway, after another reboot, Fedora came up fine. The resolution still 
looked a bit too low, though.

Resolution: 1400x1050
Monitor is correctly labelled as Dell S2209W

Resolution: 1280x720
Refresh Rate: 60Hz

But resolution offered many choices now. I changed this to 1920x1080. 
Likewise, I was able to change the refresh to 56Hz.

After the monitor blanked, my desktop was moved up and to the left, so I 
could only just see the bottom right corner. I used the panel's 
"auto-adjust" feature, and everything is now hunky-dory.

And I learned a lot about xorg.conf, which made it all worthwhile.

(ok, and the screen looks much better--let's not forget that.)

Thanks again, Frank, for the push I needed to give that site another go.

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