Comment 60 for bug 570151

I have this problem happening on a number of multi-screen machines with subtly different hardware (some i386, some amd64). Most are running with at least 3 monitors and have 2 nvidia cards but one has matrox cards. I am running some machines on 10.04.4 but some are running 10.04.2 and I am using the proprietary graphics card drivers with various versions of the drivers. All multi-screen machines have encountered the problem at some stage in the last few months.

The problem happens intermittently but, when it does, I sometimes cannot establish a remote ssh session to kill the out of control Xorg. Mostly the machine needs a hard reboot to regain control. Unfortunately, because of other proprietary software I am running, upgrading beyond 10.04 is not an option.

I did an investigation and tracked the problem down to a known freedesktop.org bug (https://bugs.freedesktop.org/show_bug.cgi?id=24986). I downloaded the Ubuntu source for xorg-server (1.7.6-2ubuntu7.11 which is associated with the latest 10.04.4 updates) and noticed that 2 of the 3 patches were not applied. I suspect the patch https://bugs.freedesktop.org/attachment.cgi?id=33908 fixes this problem. So I patched the source and applied the other Xinerama patch associated with the bug that was also missing (https://bugs.freedesktop.org/attachment.cgi?id=33939). Since applying the patches, I have not been able to reproduce the problem even on the one machine that could reliably produce the bug before applying the patches.

I have created a PPA based on the xorg-server 1.7.6-2ubuntu7.11 for 10.04.4 and simply applied the 2 missing patches from https://bugs.freedesktop.org/show_bug.cgi?id=24986. If anyone is interested, it can be found on https://launchpad.net/~glsolaria/+archive/ppa .

Since 10.04 is still LTS, and this problem is known to require a hard reboot to regain control of the machine, is there any chance these patches can be applied to 10.04? If you look at the patch https://bugs.freedesktop.org/attachment.cgi?id=33908, it gives a good description of the problem. Based on my naive reading of the patch, this bug can happen on any multi-monitor 10.04 system when the mouse pointer is moved across screens but it may be subject to a race condition thereby explaining the intermittent nature of this problem.