Dual Head doesn't work

[James Gray]

drew einhorn wrote:

> I have a couple of ATI cards.  Here's the output from lspci:
> 
> 01:00.0 VGA compatible controller: ATI Technologies Inc Radeon RV200 QW 
> [Radeon 7500]
> 02:00.0 VGA compatible controller: ATI Technologies Inc RV280 [Radeon 
> 9200 PRO] (rev 01)
> 02:00.1 Display controller: ATI Technologies Inc RV280 [Radeon 9200 PRO] 
> (Secondary) (rev 01)

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> Section "Screen"
>         Identifier      "Screen0"
>         Device          "0 ATI Technologies Inc Radeon RV200 QW [Radeon 
> 7500]"
>         Monitor         "ULTRASCAN1600HS"
>         DefaultDepth    24
>         SubSection "Display"
>                    Modes "1600x1200" "1280x1024" "1024x768" "800x600" "640x480"
>         EndSubSection
> EndSection
> 
> Section "Screen"
>         Identifier "Screen1"
>         Device "1 ATI Technologies Inc Radeon RV280 [Radeon 9200 PRO]"
>         Monitor "ULTRASCANP99"
>         Defaultdepth 24
>         SubSection "Display"
>                 Depth 24
>                 Modes "1400x1050"
>         EndSubSection
> EndSection

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> It almost works.  Both Desktops come up.
> Except the pixels at right and left edges of the desktop are are all 
> squised together
> into a bright lines.  Everything to the left of "ations" in the 
> "Applications" pulldown
> is missing on the left and everything to the right of May in the Date.

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> (==) ServerLayout "DualHead"
> (**) |-->Screen "Screen0" (0)
> (**) |   |-->Monitor "ULTRASCAN1600HS"
> (**) |   |-->Device "0 ATI Technologies Inc Radeon RV200 QW [Radeon 7500]"
> (**) |-->Screen "Screen1" (1)
> (**) |   |-->Monitor "ULTRASCANP99"
> (**) |   |-->Device "1 ATI Technologies Inc Radeon RV280 [Radeon 9200 PRO]"
> (**) |-->Input Device "Generic Keyboard"
> (**) |-->Input Device "Configured Mouse"

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> (II) Primary Device is: PCI 01:00:0
> (WW) RADEON: No matching Device section for instance (BusID PCI:2:0:1) found

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> (--) RADEON(1): Chipset: "ATI Radeon 9250 5960 (AGP)" (ChipID = 0x5960)

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> (WW) RADEON(0): No crtc mode list for crtc 1,continuing with desired mode
> disable montype: 1
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> (WW) RADEON(1): No crtc mode list for crtc 1,continuing with desired mode
> disable montype: 1

By the look of this, you've specified modes in the screen sections 
(above) but there is no matching ModeLine.  So the X server is doing its 
best to give you the resolution you asked for but the monitor timing is 
all off which is giving you the display aberrations.

Simple solution:
1. Google "X modeline calculator" (there are tons!)
2. Feed in the monitor scan ranges etc as required.
3. Cut-and-paste the generated modeline into the appropriate "Screen" 
section of /etc/X11/xorg.conf
4. Restart X.

Hope that helps :)

Cheers,

James