Two monitors, modelines, xorg.conf, and all that...

[Marko Vojinovic]

I have a laptop whose widescreen LVDS reports these modelines
(correctly, afaik):

(II) intel(0): Modeline "1280x800"x59.8   83.50  1280 1352 1480 1680
800 803 809 831 -hsync -vsync (49.7 kHz)
(II) intel(0): Modeline "1024x768"x60.0   65.00  1024 1048 1184 1344
768 771 777 806 -hsync -vsync (48.4 kHz)
(II) intel(0): Modeline "800x600"x60.3   40.00  800 840 968 1056  600
601 605 628 +hsync +vsync (37.9 kHz)
(II) intel(0): Modeline "640x480"x59.9   25.18  640 656 752 800  480
490 492 525 -hsync -vsync (31.5 kHz)

I also have a widescreen VGA monitor, reporting these:

(II) intel(0): Modeline "1680x1050"x59.9  119.00  1680 1728 1760 1840
1050 1053 1059 1080 +hsync -vsync (64.7 kHz)
(II) intel(0): Modeline "1680x1050"x60.0  146.25  1680 1784 1960 2240
1050 1053 1059 1089 -hsync +vsync (65.3 kHz)
(II) intel(0): Modeline "1400x1050"x60.0  122.00  1400 1488 1640 1880
1050 1052 1064 1082 +hsync +vsync (64.9 kHz)
(II) intel(0): Modeline "1280x1024"x75.0  135.00  1280 1296 1440 1688
1024 1025 1028 1066 +hsync +vsync (80.0 kHz)
(II) intel(0): Modeline "1280x1024"x60.0  108.00  1280 1328 1440 1688
1024 1025 1028 1066 +hsync +vsync (64.0 kHz)
(II) intel(0): Modeline "1440x900"x75.0  136.75  1440 1536 1688 1936
900 903 909 942 -hsync +vsync (70.6 kHz)
(II) intel(0): Modeline "1440x900"x59.9  106.50  1440 1520 1672 1904
900 903 909 934 -hsync +vsync (55.9 kHz)
(II) intel(0): Modeline "1280x960"x60.0  108.00  1280 1376 1488 1800
960 961 964 1000 +hsync +vsync (60.0 kHz)
(II) intel(0): Modeline "1152x864"x75.0  108.00  1152 1216 1344 1600
864 865 868 900 +hsync +vsync (67.5 kHz)
(II) intel(0): Modeline "1024x768"x75.0   78.75  1024 1040 1136 1312
768 769 772 800 +hsync +vsync (60.0 kHz)
(II) intel(0): Modeline "1024x768"x70.1   75.00  1024 1048 1184 1328
768 771 777 806 -hsync -vsync (56.5 kHz)
(II) intel(0): Modeline "1024x768"x60.0   65.00  1024 1048 1184 1344
768 771 777 806 -hsync -vsync (48.4 kHz)
(II) intel(0): Modeline "832x624"x74.6   57.28  832 864 928 1152  624
625 628 667 -hsync -vsync (49.7 kHz)
(II) intel(0): Modeline "800x600"x72.2   50.00  800 856 976 1040  600
637 643 666 +hsync +vsync (48.1 kHz)
(II) intel(0): Modeline "800x600"x75.0   49.50  800 816 896 1056  600
601 604 625 +hsync +vsync (46.9 kHz)
(II) intel(0): Modeline "800x600"x60.3   40.00  800 840 968 1056  600
601 605 628 +hsync +vsync (37.9 kHz)
(II) intel(0): Modeline "800x600"x56.2   36.00  800 824 896 1024  600
601 603 625 +hsync +vsync (35.2 kHz)
(II) intel(0): Modeline "640x480"x75.0   31.50  640 656 720 840  480
481 484 500 -hsync -vsync (37.5 kHz)
(II) intel(0): Modeline "640x480"x72.8   31.50  640 664 704 832  480
489 492 520 -hsync -vsync (37.9 kHz)
(II) intel(0): Modeline "640x480"x75.0   31.50  640 656 720 840  480
481 484 500 -hsync -vsync (37.5 kHz)
(II) intel(0): Modeline "640x480"x59.9   25.18  640 656 752 800  480
490 492 525 -hsync -vsync (31.5 kHz)
(II) intel(0): Modeline "720x400"x70.1   28.32  720 738 846 900  400
412 414 449 -hsync +vsync (31.5 kHz)

When I plug in the VGA, X chooses the highest common resolution, which
happens to be 1024x768. I can only ponder as to why a 22" VGA monitor
does not want to do 1280x800, but that's not the question. What I
would like to have is the following setup:

* when VGA is not plugged in, LVDS should be up with its native
resolution (1280x800)
* when VGA is plugged in, LVDS should be off, while VGA in its native
resolution (1680x1050)

It would be nice to have this hot-pluggable, but I don't mind
restarting X or the computer for the change. Can anybody tell me how
to configure xorg.conf to make this happen?

My current xorg.conf is fairly simple so far:

########################
Section "ServerLayout"
        Identifier     "X.org Configured"
        Screen         "Screen0"
EndSection

Section "Device"
        Option      "AccelMethod"  "XAA"
        Identifier  "Card0"
        Driver      "intel"
        VendorName  "Intel Corporation"
        BoardName   "Mobile GM965/GL960 Integrated Graphics Controller"
        BusID       "PCI:0:2:0"
EndSection

Section "Screen"
        Identifier "Screen0"
        Device     "Card0"
EndSection
########################

The AccelMethod is set to XAA because of that famous intel random
lockup thing (it doesn't eliminate the bug, just makes it more rare),
everything else is autoconfigured.

Thanks, :-)
Marko