Possible fix to Nvidia driver "no screens found" error - SLI especially.

[BusterHymen]

I have 2 GTX 275's. After installing the nvidia driver straight from the site (first the CUDA dev. driver, then the 'regular' driver), I rebooted and got the "No screens" B.S. (using BT-4R2).

I've been trying off and on for a week, trying "fix-vesa", "nvidia-xconfig", adding new sources and all that, but none of it worked.

This works for both the 'Primary display device is not PCI' and the 'No screens detected' error (for me, at least, on a couple of machines).

Go through your Xorg.0.log file until you come upon something like this:

(!!) More than one possible primary device found
(--) PCI: (0@3:0:0) nVidia Corporation GT200b [GeForce GTX 275] rev 161, Mem @ blah blah blah
(--) PCI: (0@4:0:0) nVidia Corporation GT200b [GeForce GTX 275] rev 161, Mem @ blah blah blah

TAKE NOTE OF THE CARD YOUR MAIN MONITOR IS PLUGGED INTO - Mine is PCI: (0@3:0:0) or PCI:3:0:0

The easiest way to do the next part is to get the original xorg.conf file created by nvidia-xconfig. If you can't find that, you can restore your pre-nvidia file (rename xorg.conf.backup xorg.conf) and then run nvidia-xconfig to create one.

Anyway, open your xorg.conf file and find this part:

Section "Device"
Identifier "Device0"
Driver "nvidia"
VendorName "NVIDIA Corporation"

and add this line right underneath (or really anywhere in there):

BusID "PCI:3:0:0" (remember, the numbers following "PCI: will depend on your machine)


That's it. Save the file and type "startx". Should start right up.

I'm a linux n00b, btw, but I figured I'd post this just in case - I know I haven't seen any fix like this posted anywhere... Please let me know if this works for anyone else.

[donnieneo]

I had a similar issue trying to get BT 5.1 working with a nVidia 7300 LE. After installing my nVidia driver from the website, I would run startx and it would freeze while loading up the desktop. I used the how-to by xX_Spiidey_Xx and ran apt-get install nvidia-settings. After installing nvidia-settings, I experienced the same "no screens found" error.

I found the solution at http://wiki.x.org/wiki/FAQErrorMessages. My particular error was accompanied by a message stating "Screen(s) found, but none have a usable configuration." According to wiki.x.org, this issue is often an issue with monitor ranges, and can be fixed by adjusting the depth setting. To fix the depth setting, I had to run the following commands:

vi /etc/X11/xorg.conf

This command allowed me to use VI (a built in text editor) to edit the xorg.conf file, which is where the depth setting needed adjustment.

I then scrolled down until I saw the following:

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "TwinView" "0"
    Option         "metamodes" "CRT: nvidia-auto-select +0+0; CRT: 800x600 +0+0; CRT: 640x480 +0+0"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

Section "Screen"
    Identifier     "Screen1"
    Device         "Device1"
    Monitor        "Monitor1"
    DefaultDepth    24
    Option         "TwinView" "0"
    Option         "metamodes" "DFP: nvidia-auto-select +0+0"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

I typed in "I" to edit the depth settings, here is what this section of my xorg.conf file currently looks like:

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    16
    Option         "TwinView" "0"
    Option         "metamodes" "CRT: nvidia-auto-select +0+0; CRT: 800x600 +0+0; CRT: 640x480 +0+0"
    SubSection     "Display"
        Depth       16
    EndSubSection
EndSection

Section "Screen"
    Identifier     "Screen1"
    Device         "Device1"
    Monitor        "Monitor1"
    DefaultDepth    16
    Option         "TwinView" "0"
    Option         "metamodes" "DFP: nvidia-auto-select +0+0"
    SubSection     "Display"
        Depth       16
    EndSubSection
EndSection

I then hit Escape, then typed ":wq" to save the file and quit out of VI. After this, startx runs perfectly.

It appears that this "depth" setting is short for "color depth", so if setting depth to 16 does not fix your problem, you may need to adjust it lower (8 is what wiki.x.org suggests, but that's 256 colors and looks like someone rendered your GUI using crayons).

Here are what the color depth settings are listed as on my NVIDIA X Server Settings tool, for reference:
Depth 24 - 16.7 Million Colors
Depth 16 - 65,536 Colors
Depth 15 - 32,768 Colors
Depth 8 - 256 Colors

Depth 24 was set as default for me, and I tried some other depths (depth 20, depth 18), but only the ones listed above seem to work at all. Sorry for the (possibly unnecessary) detail, figuring out this process took me about 4 hours, so I put as much detail in here as I could. Let me know if this fixes your issue, or if there's something I left out.
Good luck!