Comment 16 for bug 36461

I have been experiencing hard lockups every time I start X dualhead also, since upgrading to Ubuntu Dapper (worked fine with Breezy). The attached Xorg log file is what I'm able to grab before my system locks solidly (about 10-15 seconds after startx). Before the lockup, a normal X desktop is displayed on the ATI and the Ubuntu splash screen etc comes up, mouse moves etc. At the time of the lockup, the i810 display fills with vertical coloured bars, and the X desktop that had been displayed on the Mach64 blanks at the time the bars are displayed. Only C+A+D works after this point. N.B.: This is with the ATI Mach64 selected as the primary display in the BIOS.

Previously (on Breezy) I had to change my primary display (in PC BIOS) to be the i810 for dualhead to work at all; the complete opposite of the Windows install on the same machine, which only supports dualhead if the ATI Mach64 is primary display. Since upgrading to Dapper, selecting i810 as primary in BIOS no longer works, and X fails to intialise the ATI card which is simply ignored (although X works correctly as a single display setup on the i810).

My Xorg config utilises both Mach64 and i810, as below:

Section "Device"
        Identifier "ATI Rage Pro XL"
        Driver "ati"
        BusID "PCI:2:10:0"
EndSection

Section "Device"
        Identifier "i815"
        Driver "i810"
        BusID "PCI:0:2:0"
        VideoRAM 8192
EndSection

Section "Monitor"
        Identifier "LM-500"
        Option "DPMS"
        HorizSync 30-60
        VertRefresh 60-75
EndSection

Section "Monitor"
        Identifier "Philips 151AX"
        Option "DPMS"
        HorizSync 30-60
        VertRefresh 60-75
EndSection