Dual monitor setup using ATI HD3450

[Giles]

Hello

This is the first time I've tried to use two monitors, and so far I haven't had any success. I'm running Mandriva 2009, with the 2.6.27.19 kernel; my graphics card is an ATI Radeon HD3450 (there's an onboard nVidia card as well, but I'm not trying to use it - which is good, because Mandriva doesn't seem to recognise that it's there anymore ). I've got two generic CRT monitors, one in the HD3450's VGA port, and one in the DVI port via a DVI-to-VGA adaptor.

The graphical config in Mandriva doesn't give me any option to configure dual display at all - it doesn't even mention the possibility of switching on xinerama. I've therefore been trying to get it working by editing my xorg.conf (copying examples from the web), but so far, each time I've tried loading my new xorg.conf, X wont start at all.

I'm attaching both my old xorg.conf file, which doesn't even try to support two monitors, but does work with one, and my new one, which tries to support two monitors, but doesn't work at all!

Any thoughts gratefully received.
Thanks for your time
Giles

[coopstah13]

do you have the ATI proprietary driver installed? That is the driver you are attempting to use in the new config, but in the old config you are using the open source radeonhd driver. Try changing fglrx to radeonhd in the new file and see if that works.

[Giles]

I'm pretty sure I do have both drivers installed, yes (sorry for not mentioning that at first). I tried making the change you suggested, just to be sure, but it doesn't change anything (X still wont start when I use the new xorg.conf).

Giles

[Giles]

I don't know if this will help, but other threads I've found via google have asked people for the output of xrandr, so that's here:

Screen 0: minimum 320 x 200, current 1024 x 768, maximum 1280 x 1280
TV_7PIN_DIN disconnected
VGA_1 connected 1024x768+0+0 306mm x 230mm
   1280x1024      59.9  
   1024x768       84.9*    85.0     75.1     70.1     60.0     43.5  
   832x624        74.6  
   800x600        84.7     85.1     72.2     75.0     60.3     56.2  
   640x480        84.4     75.0     72.8     66.7     60.0  
   720x400        87.8     70.1  
DVI-I_1/digital connected 1024x768+0+0 0mm x 0mm
   1024x768       60.0* 
   800x600        60.3  
   640x480        59.9  
DVI-I_1/analog disconnected

Any thoughts anyone? (and thanks again for your time)
Giles

[Rubberman]

Switch to text mode (set /etc/inittab to run level 3 if necessary) and login as root to a console terminal (not GUI). Run the command Xorg -configure - this will probe the system for video and display hardware and create an xorg.conf file with what it finds. This is a good way to start. You can then edit the resulting file and try running X with the command "startx" before you switch back to run level 5 (X login).

Here are the xorg.conf entries for my nVidia system related to the displays and video card. Note that I am using an nVidia card and 2 flat-panel displays.

Section "Monitor"
    Identifier     "Monitor0"
    ModelName      "Dell 2407WFP (Digital)"
    HorizSync       30.0 - 83.0
    VertRefresh     56.0 - 76.0
    Option         "dpms"
EndSection

Section "Monitor"
    Identifier     "Monitor1"
    VendorName     "Monitor Vendor"
    ModelName      "Dell 2405FPW (Digital)"
    HorizSync       30.0 - 83.0
    VertRefresh     56.0 - 76.0
    Option         "dpms"
EndSection

Section "Device"
    Identifier     "Videocard0"
    Driver         "nvidia"
    BusID          "PCI:7:0:0"
    Screen          0
EndSection

Section "Device"
    Identifier     "Videocard1"
    Driver         "nvidia"
    BusID          "PCI:7:0:0"
    Screen          1
EndSection

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      "1920x1200"
    EndSubSection
EndSection

[Giles]

Hi Rubberman

I've just gone back to uni, and I've only got one monitor with me at the moment, but I'm going back home briefly over the weekend, so I'll pick up the other one then, and give xorg -configure a try.

Thanks for the suggestion - I'll report back in a couple of days.

Giles

[Giles]

I've just tried Xorg -configure, and I'm afraid it crashes my computer... Immediately after hitting enter, the screen goes black with a white underscore cursor in the top-left corner, and doesn't respond to anything (I can't even use ctrl+alt+F(n) to change to a different terminal).

This is a different crash to the one I get when I try to start X using my hand-edited xorg.conf, when the screen goes blank after a little while, then a white underscore cursor in the top-left corner *blinks on and off*, and I can use the ctrl+alt+F-key combination.

Does this behaviour suggest anything?
Thanks
Giles

Edit: P.S. the Xorg -configure crash happens before it starts trying to write a xorg.conf file. (I know that because I tried deleting xorg.conf, then running Xorg -configure, and found that xorg.conf wasn't created).

[Rubberman]

Try renaming your existing xorg.conf, to something like xorg.conf.bak, before you try Xorg -configure. The -configure option creates a new xorg.conf file after probing your hardware and is intended as a first-thing-after-installation sort of operation. It is possible that the old xorg.conf file is confusing it. If that doesn't work, then I am clueless (still).

[Giles]

Sorry Rubberman - I've tried running Xorg -configure when there's no xorg.conf file in existence, and it still doesn't work

Giles

[Rubberman]

Sorry Rubberman - I've tried running Xorg -configure when there's no xorg.conf file in existence, and it still doesn't work

Giles

Hummm (scratching head)... This is highly unusual. I assume you are running it with the GUI turned off? Xorg is very, very stable. That it crashed your system is indicating that there is something really frelled here. I wish I could be of more help. Have you looked at the Xorg log file /var/log/Xorg.log? It might give some indication of what is wrong, but "crashed the system"? That suggests that you had a kernel panic. What do you find in /var/log/messages or the output from dmesg?

Finally, please provide (if you haven't already) some details about computer hardware, setup, Linux distribution+version, and kernel rev.