注销后黑屏 不显示登录界面的问题 求助

我和室友都是 出现这个问题 关机没问题
注销或者"Ctrl+Alt+Del"后就黑屏 只能强行重启

哪位大哥给分析分析吧。
显卡是nv quando 140M
用的nv源里面的驱动

日志：
Dec 22 19:05:47 linux-kxkt kdm[2856]: X server startup timeout, terminating
Dec 22 19:06:02 linux-kxkt kdm[2856]: X server termination timeout, killing
Dec 22 19:06:03 linux-kxkt shutdown[11417]: shutting down for system reboot
Dec 22 19:06:03 linux-kxkt kdm[2856]: X server for display :0 cannot be started, session disabled
Dec 22 19:06:04 linux-kxkt init: Switching to runlevel: 6

没有，这么怪

自己顶一下 还是没有解决。。。。。
找到老外有人也出现这个问题了
First off, I have a laptop (meaning I cant change the video card) with an nVidia chipset (meaning I’d like to change the video card). So while OpenSUSE 11.1 works really nicely with the open source “nv” video driver, it can’t do any compositing, 3d, OpenGL, etc., etc. (meaning no wobbley windows or cube goodness or translucency or… you get the idea…). So I followed these nice little 1-click instructions and installed the latest stable nVidia drivers, rebooted, and up came X with nVidia’s drivers quite nicely. So far so good. And then I clicked “logout”. And that’s where things started to fall apart. It looks like what’s happening is that nVidia’s X driver gets killed when logging out and trying to log back in again. I poked around a bit and saw in a log somewhere that kdm was timing out waiting for X and ended up giving up. So I bumped up some values in /usr/share/kde4/config/kdm/kdmrc in the “X-:*-Core” section (Core config for local displays). I changed ServerAttempts to 5 and ServerTimeout to 45, and it seems to help. Mind you, the underlying problem is still there, and X takes a LOOOOONG time to restart with the nVidia drivers, but at least this keeps kdm from failing altogether and me from getting stuck without an X session and an unusable console display (when this happens, and I’ve booted with the default vga= line, the console is totally unusable).

我有时启动选择grub后就黑屏了。。其他正常，有时重启后就好了。。