xserver-xorg: - Matrox G550 Dualhead woes!

[Adrian von Bidder]

Yo!

Environment: Matrox G550 on xorg from unstable on a (mostly) sarge 
installation. 2 analog screens.  Xinerama is used, bare xorg - no mga_hal 
etc.; kernel linux-image-2.6.12 or kernel-image-2.6.8 doesn't matter; 
686-smp in both cases.  DRM loads fine.

Symptom:  booting, one display is text console.  When X is started, it 
starts fine on that display, but there's no signal on the other display - 
thus it won't even come out of power save mode.

Starting X once with a single head xorg.conf solves the problem: The 'single 
head' X delivers identical signal to both outputs of the graphics card 
(even to the point where killing X or switcing back to text mode shows the 
text mode on both screens). Changing xorg.conf back to the 
dualhead/xinerama one, it starts fine on both displays.

[ please cc: me on replies ]

Detailed information:

xorg.conf (excerpts):

=======
Section "ServerFlags"
        Option          "Xinerama" "on"
EndSection

Section "Device"
        Identifier      "Matrox Graphics, Inc. MGA G550 AGP, Screen 0"
        Driver          "mga"
        BusID           "PCI:1:0:0"
        Screen          0
EndSection

Section "Device"
        Identifier      "Matrox Graphics, Inc. MGA G550 AGP, Screen 1"
        Driver          "mga"
        BusID           "PCI:1:0:0"
        Screen          1
EndSection

Section "Screen"
        Identifier      "Screen 0"
        Device          "Matrox Graphics, Inc. MGA G550 AGP, Screen 0"
        Monitor         "Hitachi CM772"
        ...
EndSection

Section "Screen"
        Identifier      "Screen 1"
        Device          "Matrox Graphics, Inc. MGA G550 AGP, Screen 1"
        Monitor         "BenQ 7638"
        ...
EndSection

Section "ServerLayout"
        Identifier      "Default Layout"
        Screen          "Screen 0" 0 0
        Screen          "Screen 1" RightOf "Screen 0"
        InputDevice     "Generic Keyboard"
        InputDevice     "Configured Mouse"
EndSection

[Monitor sections are quite standard, but I'm specifying HorizSync and 
VertRefresh manually, as X seems to confuse the values if I try letting it 
detect them automatically.]
=======

And starting X quickly with the one below is a workaround, as described 
above.

=======
Section "Device"
        Identifier      "Matrox Graphics, Inc. MGA G550 AGP, Screen 1"
        Driver          "mga"
EndSection

Section "ServerLayout"
        Identifier      "Default Layout"
        Screen          "Screen 0"
        InputDevice     "Generic Keyboard"
        InputDevice     "Configured Mouse"
EndSection

[Screen & Monitor as above]
=======

Anybody had similar experiences, or has a G550 and does something slightly 
different?

thanks in advance.
-- vbi

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