On the eve of the next Fedora release, I thought it was time to upgrade to this one: yum --releasever=16 --disableplugin=presto distro-sync. After converting the MBR to grub2, I rebooted with no issue. Not surprisingly, the next step was dealing with X and my four monitors on three Nvidia graphics cards: two middle monitors on a dual-head GeForce 6200 NV44A AGP card, and two outside monitors on a pair of GeForce FX 5200 NV34 PCI cards. Always interesting.

I have been running the nouveau driver the last few releases with no problems, but this time as soon as nouveau took over during kernel boot, the second monitor on my dual-head card went dark: the DVI output. It is detected though, as windows can be dragged into it, and xrandr -q confirmed it is there. It is basically a black hole. Booting with only that monitor does not work either. I even booted my remaining Fedora 15 kernel into X. I had almost immediate graphics problems, but all four screens light.

I installed the proprietary kmod-nvidia-295 driver (GeForce 6+) from the RPMFusion repository. After manually adding the necessary rdblacklist=nouveau nouveau.modeset=0 bits to grub2, rebuilding initramfs with dracut, and rebooting, that lit up both middle monitors. Unfortunately, that leaves my outer monitors dark on the legacy graphics cards. Before nouveau, what I had done in the past was to install the legacy kmod-nvidia-173xx driver (GeForce 5) to drive both the GeForce 5 and the GeForce 6, a lucky compatibility coincidence. I cannot even try that here though, since the legacy drivers have not been updated to work with xorg 1.11 in Fedora 16.

Along the way, I tried a few things to see if that DVI output could be kicked to life, despite the fact it is not an xorg problem. I gave the strangely named ZaphodHeads option a shot. It treats each card output as a separate screen, allowing for maximal flexibility in layout. Great name, and neat idea, but all combinations I tried only lit up one screen. I even tried nvidia and nouveau together, but that has never and will never work. I was surprised to see X even start, though only with my middle screens lit up.

Going back to nouveau, I had to remind myself to remove the blacklist bits from grub2 after uninstalling nvidia. I had done this once before: the machine boots, and then once nouveau takes over, all graphic updates to the screen cease. I took a detour into rescue mode and the wonders of the new systemd init system before realizing that my machine really was not hanging doing a filesystem check, it just looked that way. This is a tangent, but troubleshooting systemd is a bit tortuous. All of the documentation indicates you should use the systemctl command for most functions, but since that affects the running systemd, it is all but useless in a rescue boot. If in a chroot, at least it says as much. And mucking around with the systemd filesystem to disable services is made difficult by the dependency chaining. I am reserving judgement, hoping this is a change for the better and not just a change for the change.

So I am back to nouveau, down one monitor. On the plus side, Xinerama works again to combine all screens from multiple cards into one continuous desktop. Support for this function has finally surfaced in nouveau (disables XRandR), long-missing for my hardware in Fedora. Glad to have it back.