I have a workstation with 4 graphics cards， QUADRO RTX 4000. Every graphics card connected to a 4K monitor using dp interface.
.
My OS is ubuntu20.04 lts, when i installed my os，I executed the following command：
sudo apt update
sudo apt upgrade
sudo ubuntu-drivers auto install
sudo reboot
After system restart，i run the command sudo nvidia-settings. In primary screen，I enable BaseMosaic ，and enabled other monitor with “Configuration : x screen 0”,then i apply settings and saved it in xorg.conf.
A part of my xorg.conf like this :
Section “Screen”
Identifier “Screen0”
Device “Device0”
Monitor “Monitor0”
DefaultDepth 24
Option “Stereo” “0”
Option “nvidiaXineramaInfoOrder” “DFP-2”
Option “metamodes” “GPU-772965d4-80c2-2c14-d5b2-4be8a7c3a43c.DP-2: nvidia-auto-select +0+0, GPU-b16ec084-0226-c21e-496a-193149a3140f.DP-1-2: nvidia-auto-select +3840+0, GPU-09d00272-fc4b-903f-38f8-3713733003f1.DP-2-2: nvidia-auto-select +7680+0, GPU-db7986d6-56d3-01aa-a1f3-7e520697fcbc.DP-3-2: nvidia-auto-select +11520+0”
Option “MultiGPU” “Off”
Option “SLI” “off”
Option “BaseMosaic” “on”
SubSection “Display”
Depth 24
Then i reboot again,After the restart, the displays (four monitor) all have no signal.But use other computer , i can connect the workstation with ssh.In /var/log/syslog ,i found this:
(EE) NVIDIA(GPU-0): Failed to select a display subsystem.
Fatal server error:
May 12 16:56:15 hengda172 /usr/lib/gdm3/gdm-x-session[2186]: (EE) no screens found(EE)
Error: can’t open /lib/modules/5.8.0-53-generic/updates/dkms
in /var/lib/gdm3/.local/share/xorg/Xorg.0.log, it shows :
[ 714.076] compiled for 1.6.99.901, module version = 1.0.0
[ 714.076] Module class: X.Org Server Extension
[ 714.076] (II) NVIDIA GLX Module 460.73.01 Thu Apr 1 21:35:16 UTC 2021
[ 714.076] (II) NVIDIA: The X server supports PRIME Render Offload.
[ 714.079] (II) NVIDIA(GPU-0): NVIDIA Base Mosaic enabled.
[ 714.080] (EE) NVIDIA(GPU-0): Failed to select a display subsystem.
[ 714.080] (EE) NVIDIA(GPU-0): Only one GPU will be used for this X screen.
[ 714.080] (EE) NVIDIA(GPU-0): The NVIDIA graphics device PCI:3:0:0 is part of an active SLI
[ 714.080] (EE) NVIDIA(GPU-0): configuration and is currently unavailable for single GPU
[ 714.080] (EE) NVIDIA(GPU-0): rendering. Please see Chapter 30: Configuring SLI and
[ 714.080] (EE) NVIDIA(GPU-0): Multi-GPU Mosaic in the README for troubleshooting
[ 714.080] (EE) NVIDIA(GPU-0): information.
[ 714.080] (EE) *** Aborting ***
[ 714.080] (EE) NVIDIA(0): Failing initialization of X screen
[ 714.080] (II) UnloadModule: “nvidia”
[ 714.080] (II) UnloadSubModule: “glxserver_nvidia”
[ 714.080] (II) Unloading glxserver_nvidia
[ 714.080] (II) UnloadSubModule: “wfb”
[ 714.080] (II) UnloadSubModule: “fb”
[ 714.080] () NVIDIA(G0): Depth 24, (–) framebuffer bpp 32
[ 714.081] (==) NVIDIA(G0): RGB weight 888
[ 714.081] (==) NVIDIA(G0): Default visual is TrueColor
[ 714.081] (==) NVIDIA(G0): Using gamma correction (1.0, 1.0, 1.0)
[ 714.081] (II) Applying OutputClass “nvidia” options to /dev/dri/card2
[ 714.081] () NVIDIA(G0): Option “Stereo” “0”
[ 714.081] () NVIDIA(G0): Option “nvidiaXineramaInfoOrder” “DFP-2”
[ 714.081] () NVIDIA(G0): Option “SLI” “off”
[ 714.081] () NVIDIA(G0): Option “MultiGPU” “Off”
[ 714.081] () NVIDIA(G0): Option “BaseMosaic” “on”
[ 714.081] () NVIDIA(G0): Option “AllowEmptyInitialConfiguration”
[ 714.081] () NVIDIA(G0): Stereo disabled by request
[ 714.081] () NVIDIA(G0): NVIDIA SLI disabled.
[ 714.081] () NVIDIA(G0): NVIDIA Multi-GPU disabled.
[ 714.081] (WW) NVIDIA(G0): Base Mosaic is available only on screen 0. Disabling Base
[ 714.081] (WW) NVIDIA(G0): Mosaic.
[ 714.081] (EE) NVIDIA(G0): Only one X screen is supported when Base Mosaic is enabled.
[ 714.081] (EE) NVIDIA(G0): Disabling this screen.
[ 714.081] (EE) NVIDIA(G0): Failing initialization of X screen
[ 714.081] (II) NVIDIA(G1): (GPU-2) already has an X screen assigned; skipping this GPU
[ 714.081] (II) NVIDIA(G1): screen
[ 714.081] (EE) NVIDIA(G1): Failing initialization of X screen
[ 714.081] (II) NVIDIA(G2): (GPU-3) already has an X screen assigned; skipping this GPU
[ 714.081] (II) NVIDIA(G2): screen
[ 714.081] (EE) NVIDIA(G2): Failing initialization of X screen
[ 714.081] (II) UnloadModule: “nvidia”
[ 714.081] (II) UnloadSubModule: “wfb”
[ 714.081] (II) UnloadSubModule: “fb”
[ 714.081] (II) UnloadModule: “nvidia”
[ 714.081] (II) UnloadSubModule: “wfb”
[ 714.081] (II) UnloadSubModule: “fb”
[ 714.081] (II) UnloadModule: “nvidia”
[ 714.081] (II) UnloadSubModule: “wfb”
[ 714.081] (II) UnloadSubModule: “fb”
[ 714.081] (EE) Screen(s) found, but none have a usable configuration.
[ 714.081] (EE)
Fatal server error:
[ 714.081] (EE) no screens found(EE)
[ 714.081] (EE)
Please consult the The X.Org Foundation support
at http://wiki.x.org
for help.
[ 714.081] (EE) Please also check the log file at “/var/lib/gdm3/.local/share/xorg/Xorg.0.log” for additional information.
[ 714.081] (EE)
[ 714.087] (EE) Server terminated with error (1). Closing log file.
Use ssh i sudo vi /etc/X11/xorg.conf , changed Option “BaseMosaic” “on” to Option “BaseMosaic” “off”,and reboot,then all four monitors have signal,
I mean, when I make BaseMosaic on in xorg.conf, there will be no signal on the displays after ubuntu startup, and when I turn off this configuration, there will be signal on the displays after startup.
Please how to solve this problem？thanks！！