HOWTO: dualhead with xorg 6.8.2 on intel i810

By dave on August 16, 2006 10:37 PM | Permalink

As I said here, I've upgraded the webserver. Along the way, there's lots of things which need fixing.

Today's project as go get the onboard graphics on the new motherboard (a ConRoe945G-DVI) working in dualhead mode with one desktop spanning two 17" monitors.

The onboard graphics is an Intel GMA950 chipset, capable of powering two outputs (one DVI, one VGA) and should, in theory, be easily capable of dualhead.

Without too much ado, here's the xorg.conf file for i810 powering two Eizo L685 LCDs. It's pretty straightforward, the only critical part is the "Device" section:

Section "Device"

Identifier "Device0"

Driver "i810"

BusID "PCI:0:2:0"

Screen 0

Option "MonitorLayout" "DFP,CRT"

Option "DisplayInfo" "False"

Option "VideoRAM" "32768"

Option "DRI" "True"

Option "XvMCSurfaces" "6"

EndSection

Section "Device"

Identifier "Device1"

Driver "i810"

BusID "PCI:0:2:0"

Screen 1

Option "MonitorLayout" "DFP,CRT"

Option "DisplayInfo" "False"

Option "VideoRAM" "32768"

Option "DRI" "True"

Option "XvMCSurfaces" "6"

EndSection

That MonitorLayout option is the critical element. Don't put "CRT,LFP" as most of the advice says, because LFP is only for directly attached flat panels (i.e., laptop displays). Also, one of the options is CRT because of the output from the graphics card, not the input to the monitor.

UPDATE: And you know something? the 2D quality on the CRT head is *far* superior to the image quality on the CRT output from any nvidia card. It's basically indistinguishable from the DVI head, and both are right up there with the old Matrox card for quality. If you want a decent dual-head motherboard, this one really does have it right out of the box.

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