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I am running Ubuntu on a Mac Pro with a Apple monitor. The machine has a GeForce GT 120 (aka GeForce 9500GT). The DVI output is still working, but the screen connected to the 'mini-displayport' doesn't work anymore. Things were working perfect in 11.10. After upgrading to 12.04, X fails to start. I did a clean install of Ubuntu 12.04 and initially things seemed to be working, but after a few reboots I got exactly the same errors.

The weird thing is that the errors seem to happen quite randomly. Once in a while, X starts fine and everything is OK. But most of the times, X fails to start. There are two errors that I see in my log files:

  • "Screen(s) found, but none have a usable configuration."
  • "Failed to tear down EVO channel"

Some info about my setup:

Some info about the HW:

jeroen@jeroen-ubuntu:~$ jockey-text -l
xorg:nvidia_current - NVIDIA accelerated graphics driver (Proprietary, Enabled, In use)
xorg:nvidia_current_updates - NVIDIA accelerated graphics driver (post-release updates) (Proprietary, Disabled, Not in use)

jeroen@jeroen-ubuntu:~$ lspci | grep VGA
05:00.0 VGA compatible controller: NVIDIA Corporation G96 [GeForce 9500 GT] (rev a1)
jeroen@jeroen-ubuntu:~$ sudo lshw -C video
       description: VGA compatible controller
       product: G96 [GeForce 9500 GT]
       vendor: NVIDIA Corporation
       physical id: 0
       bus info: pci@0000:05:00.0
       version: a1
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress vga_controller bus_master cap_list rom
       configuration: driver=nvidia latency=0
       resources: irq:16 memory:8a000000-8affffff memory:80000000-87ffffff memory:88000000-89ffffff ioport:3000(size=128) memory:8b000000-8b07ffff
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hi - can you post your /etc/X11/xorg.conf file as well please. thanks. – fossfreedom May 1 '12 at 15:08
Ok done. I ran nvidia-xconfig one more time before pasting it. – Jeroen May 1 '12 at 18:17
up vote 1 down vote accepted

By now I am fairly certain that this was in fact a bug in nvidia drivers that has been introduced in 295.40. I resolved my problem by downgrading nvidia-current to version 290 using instructions from here: Downgrading nvidia drivers in Precise. Everything seems to be running smooth again.

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