Debian 10, 2 NVS 510 cards, Base Mosaic failure

Graphics / Linux Linux
1

Fresh install Debian 10 base system. I run apt install nvidia-driver and then sudo nvidia-settings

I have three NVS 510 cards installed in this system, but for this simple test they are arranged as follows:

GPU0: 1 single LG 1920x1080 screen
GPU1: 1 single LG 1920x1080 screen
GPU2: Nothing connected

The only changes i make are the enabling of BaseMosaic and setting the 2nd monitor on the same X screen as the first monitor. I have them side by side.

Applying the settings doesn’t work because it requires a restart of the X server, so I use the nvidia settings application to save the X configuration as /etc/X11/xorg.conf.

Opening a terminal and running service display-manager restart gives me a black screen.
Via SSH, I can log in and see the following in the Xorg.0.log:

[     5.915] (**) NVIDIA(0): Depth 24, (--) framebuffer bpp 32
[     5.915] (==) NVIDIA(0): RGB weight 888
[     5.915] (==) NVIDIA(0): Default visual is TrueColor
[     5.915] (==) NVIDIA(0): Using gamma correction (1.0, 1.0, 1.0)
[     5.915] (**) NVIDIA(0): Option "Stereo" "0"
[     5.915] (**) NVIDIA(0): Option "nvidiaXineramaInfoOrder" "DFP-1"
[     5.915] (**) NVIDIA(0): Option "SLI" "off"
[     5.915] (**) NVIDIA(0): Option "MultiGPU" "Off"
[     5.915] (**) NVIDIA(0): Option "BaseMosaic" "on"
[     5.916] (**) NVIDIA(0): Stereo disabled by request
[     5.916] (**) NVIDIA(0): NVIDIA SLI disabled.
[     5.916] (**) NVIDIA(0): NVIDIA Multi-GPU disabled.
[     5.916] (**) NVIDIA(0): Option "MetaModes" "GPU-e4bbb1c5-499f-0a22-e113-fa8b260c706d.DP-1: nvidia-auto-select +0+0, GPU-4e0c41bc-2a23-ae2c-d859-e4c5807daf81.DP-1: nvidia-auto-select +0+1080"
[     5.916] (**) NVIDIA(0): Enabling 2D acceleration
[     5.916] (II) Loading sub module "glxserver_nvidia"
[     5.916] (II) LoadModule: "glxserver_nvidia"
[     5.917] (II) Loading /usr/lib/xorg/modules/extensions/libglxserver_nvidia.so
[     6.025] (II) Module glxserver_nvidia: vendor="NVIDIA Corporation"
[     6.025]    compiled for 4.0.2, module version = 1.0.0
[     6.025]    Module class: X.Org Server Extension
[     6.026] (II) NVIDIA GLX Module  418.197.02  Thu Mar 18 22:32:24 UTC 2021
[     6.697] (II) NVIDIA(GPU-0): NVIDIA Base Mosaic enabled.
[     6.723] (EE) NVIDIA(GPU-0): Failed to select a display subsystem.
[     7.437] (EE) NVIDIA(GPU-0): Only one GPU will be used for this X screen.
[     7.441] (EE) NVIDIA(GPU-0): Failed to select a display subsystem.
[     7.441] (EE) NVIDIA(0): Failing initialization of X screen 0
[     7.441] (II) UnloadModule: "nvidia"
[     7.441] (II) UnloadSubModule: "glxserver_nvidia"
[     7.441] (II) Unloading glxserver_nvidia
[     7.441] (II) UnloadSubModule: "wfb"
[     7.441] (II) UnloadSubModule: "fb"
[     7.441] (EE) Screen(s) found, but none have a usable configuration.
[     7.441] (EE)
Fatal server error:
[     7.442] (EE) no screens found(EE)
[     7.442] (EE)
Please consult the The X.Org Foundation support
         at http://wiki.x.org
 for help.
[     7.442] (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information.
[     7.442] (EE)
[     7.445] (EE) Server terminated with error (1). Closing log file.

Any idea why this fails so completely?

2

And why are you on such an ancient driver branch? The latest (and last) driver branch that works on that is the 470 series.

3

Couple reasons:

Based on Debian’s documentation NvidiaGraphicsDrivers the newest version from buster-backports is 460.73.01, which is where I started. That gave me an SLI error detailed in this ticket:

Based on the advice there I backed off to 418 as per the Debian documentation.

I can certainly try the 470 branch, it’s not in the Debian repo but that should be trivial to install. Lemme report back.

4

Enabling BaseMosaic as per the first post, same result (no X output at all). Going to the 470 drivers gives me the SLI error I was getting from the other thread.

[   147.765] (II) NVIDIA(GPU-0): NVIDIA Base Mosaic enabled.
[   147.766] (EE) NVIDIA(GPU-0): Failed to select a display subsystem.
[   147.766] (EE) NVIDIA(GPU-0): Only one GPU will be used for this X screen.
[   147.766] (EE) NVIDIA(GPU-0): The NVIDIA graphics device PCI:2:0:0 is part of an active SLI
[   147.766] (EE) NVIDIA(GPU-0):     configuration and is currently unavailable for single GPU
[   147.766] (EE) NVIDIA(GPU-0):     rendering.  Please see Chapter 30: Configuring SLI and
[   147.766] (EE) NVIDIA(GPU-0):     Multi-GPU Mosaic in the README for troubleshooting
[   147.766] (EE) NVIDIA(GPU-0):     information.
[   147.766] (EE)  *** Aborting ***
[   147.766] (EE) NVIDIA(0): Failing initialization of X screen
[   147.766] (II) UnloadModule: "nvidia"
[   147.766] (II) UnloadSubModule: "glxserver_nvidia"
[   147.766] (II) Unloading glxserver_nvidia
[   147.766] (II) UnloadSubModule: "wfb"
[   147.766] (II) UnloadSubModule: "fb"
[   147.766] (**) NVIDIA(G0): Depth 24, (--) framebuffer bpp 32
[   147.766] (==) NVIDIA(G0): RGB weight 888
[   147.766] (==) NVIDIA(G0): Default visual is TrueColor
[   147.766] (==) NVIDIA(G0): Using gamma correction (1.0, 1.0, 1.0)
[   147.766] (**) NVIDIA(G0): Option "Stereo" "0"
[   147.766] (**) NVIDIA(G0): Option "nvidiaXineramaInfoOrder" "DFP-1"
[   147.766] (**) NVIDIA(G0): Option "SLI" "off"
[   147.766] (**) NVIDIA(G0): Option "MultiGPU" "Off"
[   147.766] (**) NVIDIA(G0): Option "BaseMosaic" "on"
[   147.767] (**) NVIDIA(G0): Stereo disabled by request
[   147.767] (**) NVIDIA(G0): NVIDIA SLI disabled.
[   147.767] (**) NVIDIA(G0): NVIDIA Multi-GPU disabled.
[   147.767] (WW) NVIDIA(G0): Base Mosaic is available only on screen 0.  Disabling Base
[   147.767] (WW) NVIDIA(G0):     Mosaic.
[   147.767] (EE) NVIDIA(G0): Only one X screen is supported when Base Mosaic is enabled.
[   147.767] (EE) NVIDIA(G0):     Disabling this screen.
[   147.767] (EE) NVIDIA(G0): Failing initialization of X screen
[   147.767] (II) NVIDIA(G1):  (GPU-2) already has an X screen assigned; skipping this GPU
[   147.767] (II) NVIDIA(G1):     screen
[   147.767] (EE) NVIDIA(G1): Failing initialization of X screen
[   147.767] (II) UnloadModule: "nvidia"
[   147.767] (II) UnloadSubModule: "wfb"
[   147.767] (II) UnloadSubModule: "fb"
[   147.767] (II) UnloadModule: "nvidia"
[   147.767] (II) UnloadSubModule: "wfb"
[   147.767] (II) UnloadSubModule: "fb"
[   147.767] (EE) Screen(s) found, but none have a usable configuration.
[   147.767] (EE)
Fatal server error:
[   147.767] (EE) no screens found(EE)
[   147.767] (EE)
Please consult the The X.Org Foundation support
         at http://wiki.x.org

nvidia-bug-report.log.gz (2.3 MB)

5

A good but frustrating update, the Xorg log in the last update shows the text The NVIDIA graphics device PCI:2:0:0 is part of an active SLI configuration.
Literally at a loss of what to change I went in and arbitrarily set the Device to point at BusID 1:0:0 instead of 2:0:0

The resulting Xorg log complained that 2:0:0 is actually the main device and should be specified in xorg.conf
So all I did was change it back to 2:0:0

Now I have perfectly working BaseMosaic in Debian; two connected physical displays, connected on 2 different NVS 510 video cards, merged into the same X window and working as expected. I wish I knew what actually fixed things, but there you have it.

My next step is to get to a full 9 monitor configuration across 3 cards and I believe I should be able to do this simply by adding additional metamode values in the Xorg.conf.

Thanks for all who helped, sorry my answer is a mystery to me.