ArchLinux Xorg dual Nvidia GPU and 6 monitors - Is this even possible?

Hi, I have been having dream since I been little to have 6 monitors working . Saw it in a movie and wanted to have it since.

However a year ago I tried to realize that dream. But I have since that tried to get a working Xorg but it have not been possible. From reading google it looks like this may not be easy solvable. So this is my last cry for help before I give up and just get rid of 2 monitors. As I have successfully get 4 monitors working as long they are connected to one of the GPU.

So I hope that someone more knowledge them me could check if this is even possible.

What happens is with xinerama is enabled all screen is black. If I not use xinerama just the monitors that is connected to my secondary GPU is not enabled or black.

Closest I have been is having 5 monitors connected but no windows manager running on the two connected to secondary gpu but then I can start program with them by set the DISPLAY parameters. Problem is then that all applications is started on my center screen and if I drag them to another monitors they just jump back to one monitor. So not any monitors except one can be used even if there is a window manager running or not on them.

Here is the latest Xorg I have tried with but I have several versions that have tried. The one generated with nvidia-settings just do not work at all for me.

##############################################################

Server layout

##############################################################

Section “ServerLayout”
Identifier “Default Layout”
Screen 0 “Screen0” 12800 0
Screen 1 “Screen0” 10240 0
Screen 2 “Screen0” 7680 0
Screen 3 “Screen0” 5120 0
Screen 4 “Screen0” 2560 0
Screen 5 “Screen0” 0 0

InputDevice    "Keyboard0" "CoreKeyboard"
InputDevice    "Mouse0" "CorePointer"
Option         "Xinerama" "1"

EndSection

Section “InputDevice”
Identifier “Mouse0”
Driver “mouse”
Option “Protocol” “auto”
Option “Device” “/dev/psaux”
Option “Emulate3Buttons” “no”
Option “ZAxisMapping” “4 5”
EndSection

Section “InputDevice”
Identifier “Keyboard0”
Driver “kbd”
EndSection

###########################################################

Monitors

###########################################################

Section “Monitor”
Identifier “Monitor0”
VendorName “Unknown”
ModelName “Ancor Communications Inc ASUS PB277”
HorizSync 24.0 - 120.0
VertRefresh 50.0 - 76.0
EndSection

Section “Monitor”
Identifier “Monitor1”
VendorName “Unknown”
ModelName “Ancor Communications Inc ASUS PB277”
HorizSync 24.0 - 120.0
VertRefresh 50.0 - 76.0
EndSection

Section “Monitor”
Identifier “Monitor2”
VendorName “Unknown”
ModelName “Ancor Communications Inc ASUS PB277”
HorizSync 24.0 - 120.0
VertRefresh 50.0 - 76.0
EndSection

Section “Monitor”
Identifier “Monitor3”
VendorName “Unknown”
ModelName “Ancor Communications Inc ASUS PB278”
HorizSync 24.0 - 99.0
VertRefresh 24.0 - 76.0
EndSection

Section “Monitor”
Identifier “Monitor5”
VendorName “Unknown”
ModelName “Ancor Communications Inc ASUS PB278”
HorizSync 24.0 - 99.0
VertRefresh 50.0 - 75.0
EndSection

Section “Monitor”
Identifier “Monitor5”
VendorName “Unknown”
ModelName “Ancor Communications Inc ASUS PB278”
HorizSync 24.0 - 99.0
VertRefresh 50.0 - 75.0
EndSection

#########################################################

Devices

#########################################################

Section “Device”
Identifier “Device0”
Driver “nvidia”
VendorName “NVIDIA Corporation”
BoardName “GeForce GTX 1080 Ti”
BusID “PCI:29:0:0”
Screen 0
EndSection

Section “Device”
Identifier “Device1”
Driver “nvidia”
VendorName “NVIDIA Corporation”
BoardName “GeForce GTX 1080 Ti”
BusID “PCI:29:0:0”
Screen 1
EndSection

Section “Device”
Identifier “Device2”
Driver “nvidia”
VendorName “NVIDIA Corporation”
BoardName “GeForce GTX 1080 Ti”
BusID “PCI:29:0:0”
Screen 2
EndSection

Section “Device”
Identifier “Device3”
Driver “nvidia”
VendorName “NVIDIA Corporation”
BoardName “GeForce GTX 1080 Ti”
BusID “PCI:29:0:0”
Screen 3
EndSection

Section “Device”
Identifier “Device4”
Driver “nvidia”
VendorName “NVIDIA Corporation”
BoardName “GeForce GTX 760”
BusID “PCI:30:0:0”
Screen 4
EndSection

Section “Device”
Identifier “Device5”
Driver “nvidia”
VendorName “NVIDIA Corporation”
BoardName “GeForce GTX 760”
BusID “PCI:30:0:0”
Screen 5
EndSection

#########################################################

Screens

#########################################################

Section “Screen”
Identifier “Screen0”
Device “Device0”
Monitor “Monitor0”
DefaultDepth 24
Option “Stereo” “0”
Option “SLI” “Off”
Option “MultiGPU” “Off”
Option “BaseMosaic” “off”
Option “nvidiaXineramaInfoOrder” “DFP-0”
Option “metamodes” “DP-4: nvidia-auto-select +0+0”
SubSection “Display”
Depth 24
EndSubSection
EndSection

Section “Screen”
Identifier “Screen1”
Device “Device1”
Monitor “Monitor1”
DefaultDepth 24
Option “Stereo” “0”
Option “SLI” “Off”
Option “MultiGPU” “Off”
Option “BaseMosaic” “off”
Option “nvidiaXineramaInfoOrder” “DFP-0”
Option “metamodes” DVI-D-0: nvidia-auto-select +0+0"
SubSection “Display”
Depth 24
EndSubSection
EndSection

Section “Screen”
Identifier “Screen2”
Device “Device2”
Monitor “Monitor2”
DefaultDepth 24
Option “Stereo” “0”
Option “SLI” “Off”
Option “MultiGPU” “Off”
Option “BaseMosaic” “off”
Option “nvidiaXineramaInfoOrder” “DFP-0”
Option “metamodes” “HDMI-0: nvidia-auto-select +0+0”
SubSection “Display”
Depth 24
EndSubSection
EndSection

Section “Screen”
Identifier “Screen3”
Device “Device3”
Monitor “Monitor3”
DefaultDepth 24
Option “Stereo” “0”
Option “SLI” “Off”
Option “MultiGPU” “Off”
Option “BaseMosaic” “off”
Option “nvidiaXineramaInfoOrder” “DFP-0”
Option “metamodes” “DP-2: nvidia-auto-select +0+0”
SubSection “Display”
Depth 24
EndSubSection
EndSection

Section “Screen”
Identifier “Screen4”
Device “Device4”
Monitor “Monitor4”
DefaultDepth 24
Option “Stereo” “0”
Option “SLI” “Off”
Option “MultiGPU” “Off”
Option “BaseMosaic” “off”
Option “nvidiaXineramaInfoOrder” “DFP-0”
Option “metamodes” “DVI-I-1: nvidia-auto-select +0+0”
SubSection “Display”
Depth 24
EndSubSection
EndSection

Section “Screen”
Identifier “Screen5”
Device “Device5”
Monitor “Monitor5”
DefaultDepth 24
Option “Stereo” “0”
Option “SLI” “Off”
Option “MultiGPU” “Off”
Option “BaseMosaic” “off”
Option “nvidiaXineramaInfoOrder” “DFP-0”
Option “metamodes” “DVI-D-0: nvidia-auto-select +0+0”
SubSection “Display”
Depth 24
EndSubSection
EndSection

Here is from “nvidia-xconfig --query-gpu-info”

⬢ ~ nvidia-xconfig --query-gpu-info
Number of GPUs: 2

GPU #0:
Name : GeForce GTX 1080 Ti
UUID : GPU-4af4211b-e28f-92a7-b714-8f70fa44fef0
PCI BusID : PCI:29:0:0

Number of Display Devices: 4

Display Device 0 (TV-0):
EDID Name : Ancor Communications Inc ASUS PB277
Minimum HorizSync : 24.000 kHz
Maximum HorizSync : 120.000 kHz
Minimum VertRefresh : 50 Hz
Maximum VertRefresh : 76 Hz
Maximum PixelClock : 330.000 MHz
Maximum Width : 2560 pixels
Maximum Height : 1440 pixels
Preferred Width : 2560 pixels
Preferred Height : 1440 pixels
Preferred VertRefresh : 75 Hz
Physical Width : 600 mm
Physical Height : 340 mm

Display Device 1 (TV-1):
EDID Name : Ancor Communications Inc ASUS PB278
Minimum HorizSync : 24.000 kHz
Maximum HorizSync : 99.000 kHz
Minimum VertRefresh : 24 Hz
Maximum VertRefresh : 76 Hz
Maximum PixelClock : 330.000 MHz
Maximum Width : 2560 pixels
Maximum Height : 1440 pixels
Preferred Width : 2560 pixels
Preferred Height : 1440 pixels
Preferred VertRefresh : 60 Hz
Physical Width : 600 mm
Physical Height : 340 mm

Display Device 2 (TV-4):
EDID Name : Ancor Communications Inc ASUS PB277
Minimum HorizSync : 24.000 kHz
Maximum HorizSync : 120.000 kHz
Minimum VertRefresh : 50 Hz
Maximum VertRefresh : 76 Hz
Maximum PixelClock : 300.000 MHz
Maximum Width : 2560 pixels
Maximum Height : 1440 pixels
Preferred Width : 2560 pixels
Preferred Height : 1440 pixels
Preferred VertRefresh : 75 Hz
Physical Width : 600 mm
Physical Height : 340 mm

Display Device 3 (TV-6):
EDID Name : Ancor Communications Inc ASUS PB277
Minimum HorizSync : 24.000 kHz
Maximum HorizSync : 120.000 kHz
Minimum VertRefresh : 50 Hz
Maximum VertRefresh : 76 Hz
Maximum PixelClock : 300.000 MHz
Maximum Width : 2560 pixels
Maximum Height : 1440 pixels
Preferred Width : 2560 pixels
Preferred Height : 1440 pixels
Preferred VertRefresh : 75 Hz
Physical Width : 600 mm
Physical Height : 340 mm

GPU #1:
Name : GeForce GTX 760
UUID : GPU-98f2c1ff-4d80-a86d-9fa1-61576f04166a
PCI BusID : PCI:30:0:0

Number of Display Devices: 2

Display Device 0 (TV-0):
EDID Name : Ancor Communications Inc ASUS PB278
Minimum HorizSync : 24.000 kHz
Maximum HorizSync : 99.000 kHz
Minimum VertRefresh : 50 Hz
Maximum VertRefresh : 75 Hz
Maximum PixelClock : 330.000 MHz
Maximum Width : 2560 pixels
Maximum Height : 1440 pixels
Preferred Width : 2560 pixels
Preferred Height : 1440 pixels
Preferred VertRefresh : 60 Hz
Physical Width : 600 mm
Physical Height : 340 mm

Display Device 1 (TV-3):
EDID Name : Ancor Communications Inc ASUS PB278
Minimum HorizSync : 24.000 kHz
Maximum HorizSync : 99.000 kHz
Minimum VertRefresh : 50 Hz
Maximum VertRefresh : 75 Hz
Maximum PixelClock : 330.000 MHz
Maximum Width : 2560 pixels
Maximum Height : 1440 pixels
Preferred Width : 2560 pixels
Preferred Height : 1440 pixels
Preferred VertRefresh : 60 Hz
Physical Width : 600 mm
Physical Height : 340 mm

⬢ ~ lspci -v |grep VGA
1d:00.0 VGA compatible controller: NVIDIA Corporation GP102 [GeForce GTX 1080 Ti] (rev a1) (prog-if 00 [VGA controller])
1e:00.0 VGA compatible controller: NVIDIA Corporation GK104 [GeForce GTX 760] (rev a1) (prog-if 00 [VGA controller])

Let me know if this is even solvable or if more information is required for get any help in this. I will be happy for any info at all regarding this problem even if you don’t have the full solution.

Some more information that could be valuable

⬢ ~ pacman -Q |grep nvidia
lib32-nvidia-utils 440.82-1
nvidia 440.82-3
nvidia-installer 1.17-2
nvidia-settings 440.82-1
nvidia-utils 440.82-1
opencl-nvidia 440.82-1

⬢ ~ uname -a
Linux desktop 5.6.4-arch1-1 #1 SMP PREEMPT Mon, 13 Apr 2020 12:21:19 +0000 x86_64 GNU/Linux

Some more info

⬢ ~ lsmod |grep nvidia
nvidia_drm 53248 8
nvidia_modeset 1118208 22 nvidia_drm
nvidia 20504576 1957 nvidia_modeset
drm_kms_helper 241664 1 nvidia_drm
ipmi_msghandler 73728 2 ipmi_devintf,nvidia
drm 565248 11 drm_kms_helper,nvidia_drm

This won’t really work with that hardware setup, one 1080ti(Pascal)+760(Kepler). You should be able to get a desktop with 6 Monitors using Xinerama but you will lose gpu accel and compositing, so only few DEs will work but not good.
What kind of CPU do you have, does it have an integrated graphics that can be enabled? Then you could use PRIME.

Thanks for the reply it is rely appreciated! Even a response as this will not work is good for me because then I can move on with life and not fiddling with Xorg config until I get grey hair.

I have a AMD Ryzen 7 2700X Eight-Core Processor and it do not look like it have integrated graphics.
My DE is KDE plasma5 but as you mention I may be able to get it to work without gpu accell and compositing. So will give that a try. Guess I first need to disable compositing in KDE and then try to enable Xinerama. Will give that a try. Thanks…

With KDE, disabling the kscreen2 service and then playing with the options nvidia-settings gives you should be a comfortable way of testing things.
Getting a cheap recent amd graphics and using that as a display extender using PRIME might be an alternative.

Thanks, I disabled composite and kscreen2 as a background service in KDE. Started testing, but as soon I enable Xinerama all screens gets black. I think it is time to realise that I’m defeated. My backup plan is to get rid off 3 monitors the 760 gpu and buy 1 Ultra wide monitor to use with the 3 monitors that I have and connect all of them to the 1 GPU Titan so I have 4 monitors total but one of these are like 2. Think that will be the simplest solution for me.