When I'm running on 2 screens (extended desktop via XRandR) or had a 2nd screen connected during the same X session, X segfaults when running a Wine program.
It can take a minute before anything strange happens, but it can also happen immediately. Sometimes X locks up, and sometimes X restarts suddenly.
On Ubuntu Maverick it happens sometimes, but on Natty it happens always. And I don't like to downgrade just for using my Wine programs on 2 screens.

Xorg.0.log: http://pastebin.com/AzVruT8d

dmesg shows absolutely nothing about the crash. The only thing that appears in dmesg after the crash, is that I've pushed Alt-SysRq and K, and that the kernel had killed X because of that sysrq magic key.

It happens when running Nouveau, but does not happen with the proprietary driver. Probably this is because the proprietary driver does not use XRandR.
I cannot use that driver; it contains a bug which makes it impossible to run some of my Wine programs on 2 screens.

It happens with all Wine programs I've tried. When there has not been a 2nd screen connected during the whole X session, it just works.

lspci: http://pastebin.com/Ks3ri3jZ
Intel Core 2 Duo 1667 MHz, 3GB RAM.

HP Pavilion dv6730ed laptop. The second screen, connected via VGA, is an ADI Microscan LM-1564 CRT monitor, with resolution 1024x768@75Hz set. It is capable of 1280x1024 but I don't like that resolution; with this one, the text is just as big as on my laptop screen.

I hope that I've given enough information. Note that this may also be an XRandR or X server bug.

By the way. If it happens that X does not segfault, I am not able to extend a window from Wine over the second screen. There's also a Wine bug involved here, but as it works with the blob I think there's something wrong with Nouveau that prevents me from extending that window. Native Linux (GTK and Qt) windows just extend without problem.