Comment 2 for bug 258357

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Benjamin Redelings (benjamin-redelings) wrote : Re: Latest NVIDIA drivers: X hangs with blank screen after logout.

It seems that what is happening is this:

When X uses the nvidia driver (but not the nv driver) it hangs for about 10 seconds before starting. During this hang, I cannot switch to a VT, and the backlight is on. Eventually, however, the backlight turns off, the nVidia logo flashes on the screen, and then X starts.

However, if X is run by GDM, then GDM does not wait long enough for this process to finish. So, just as X is actually starting, GDM decides that it has failed and kills the X server before it can finish starting. Then it tries again.

After it has tried several times, it then tries to run the "fail-safe" mode with a lower resolution (800x600). However, it fails to draw it correctly, and part of the screen contains garbage, part of the left side of the window is drawn on the right side of the screen, etc.

So, it seems that something is causing the 177 nvidia driver to hang temporarily on startup. This is what causes the problem.

I also tried this with an /etc/X11/xorg.conf that was freshly generated from dexconf, and has almost no actual settings in it. (I guess the 1.5 X server is supposed to auto-detect these.) This xorg.conf works - but it uses the nv driver. If I add one line to switch to the nvidia driver, then it hangs.

I am still not sure exactly where in the startup sequence it is hanging.