[SATLUG] ATI dualhead config

Borries Demeler demeler at biochem.uthscsa.edu
Sun Apr 6 18:27:47 CDT 2008


Hi,

I am trying to get my ATI to work properly with a dual display. I can get the
Xinerama option to work fine with RightOf/LeftOf multihead layout, but I cannot
figure out how to get the clone option to work properly (where I can see the same desktop
on the laptop as on the second display). 

My laptop display is 1920x1200, my external monitor is 1600x1200. On my old nvidia
card I was able to have it running in clone mode, and the smaller 1600x1200 monitor
would show up cloned inside the 1920x1200 screen, just taking up 1600 pixels, leaving
the rest of the width of the laptop monitor undisplayed in the external monitor. So, 
when maximizing a presentation in the external monitor, the entire application would be
visible. The way I have it running right now, only the laptop monitor shows the entire 
entire application.

So, when I use:

Section "ServerLayout"
        Identifier     "Multihead layout"
        Screen      0  "Screen0" RightOf "Screen1"
        InputDevice    "Keyboard0" "CoreKeyboard"
        InputDevice    "Mouse0" "CorePointer"
        Option         "Xinerama" "on"
        Option         "Clone" "on"
EndSection

I get a cloned window, but the external 1600x1200 display is now using a virtual
screen size of 1920x1200. Worse yet, any maximized presentation can only be seen partially on the 
external monitor. Right now my only way to make the external screen have a non-virtual 
geometry is if I turn "Clone" "off", but then I get two separate screens, which is inconvenient
for presentations where my back is turned to the screen. I still can 
move between the screens using the mouse. So this configuration gives me 2 separate screens:

Section "ServerLayout"
        Identifier     "Multihead layout"
        Screen      0  "Screen0" LeftOf "Screen1"
        InputDevice    "Keyboard0" "CoreKeyboard"
        InputDevice    "Mouse0" "CorePointer"
        Option         "Xinerama" "on"
        Option         "Clone" "off"
EndSection

this (or "RightOf") works fine and as advertised.

Here are my two screen definitions:

Section "Screen"
        Identifier "Screen0"
        Device     "Videocard0"
        Monitor    "Monitor0"
        DefaultDepth     24
        SubSection "Display"
                Viewport   0 0
                Depth     24
                Modes    "1920x1200"
        EndSubSection
EndSection

Section "Screen"
        Identifier "Screen1"
        Device     "Videocard1"
        Monitor    "Monitor1"
        DefaultDepth     24
        SubSection "Display"
                Viewport   0 0
                Depth     24
                Modes    "1600x1200"
        EndSubSection
EndSection

I should mention that this is on a X1400 ATI Radeon Mobility, using the proprietary ATI fglrx driver.

Any suggestions on how to get it to clone the smaller screen within the larger screen, and not
the other way around?

Thanks, -Borries


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