2017 15" Dell Precision 5520 (Q M1200) [7th,4C,H] + GTX 1070 @ 32Gbps-TB3 (AKiTiO Node) + Linux Manjaro 18 [Random_Jerk]  

System specs:

• CPU:Intel Core i7-7820HQ
• Laptop : 2017 Dell Precision 5520
• RAM: 16 GB (2x8 GB) 2400MHz
• iGPU: Intel® HD Graphics 630 0.35-1.1 GHz
• dGPU: NVIDIA GM107GLM [Quadro M1200 Mobile]
• OS: Manjaro 18 with KDE 5.14.4 with Kernel 4.19.x/4.20.x
• External display: Dell 27 inch 4K
• Thunderbolt port has only 2 PCIe lanes assigned (Major bottleneck)

   

• Akitio Node NODE-T3IA-AKTU
• nVidia GeForce GTX 1070 8 GB
• Small Thunderbolt 3 cable
• eGPU to External Dell 4K Monitor connection through Display Port

3) Connect in the eGPU and check if its detected. (For some laptops, Thunderbolt devices should be authorized. I changed by Thunderbolt settings to make sure it was in Secure Mode in the BIOS. Once the Secure Mode has been set in the BIOS, Manjaro automagically detected it)

Section "ServerLayout"
   Identifier "egpu"
   Screen 0 "nvidiaegpu"
   Inactive "intel"
EndSection

Section "ServerLayout"
   Identifier "laptop"
   Screen 0 "intel"
   Inactive "nvidiaegpu"
EndSection

Section "Device"
   Identifier "nvidiaegpu"
   Driver "nvidia"
   BusID "PCI:11:0:0"
   #BusID in decimal, convert from hex
   Option "AllowEmptyInitialConfiguration"
   Option "AllowExternalGpus"
   Option "RegistryDwords" "PerfLevelSrc=0x2222"
EndSection

Section "Screen"
   Identifier "nvidiaegpu"
   Device "nvidiaegpu"
   Option "metamodes" "nvidia-auto-select +0+0 {ForceCompositionPipeline=On}"
   Option "TripleBuffer" "on"
   Option "AllowIndirectGLXProtocol" "off"
   Option "Coolbits" "4"
EndSection

Section "Device"
   Identifier "intel"
   Driver "modesetting"
   BusID "PCI:0:2:0"
EndSection

Section "Screen"
   Identifier "intel"
   Device "intel"
EndSection

(Note that the Bus ID of the eGPU GTX 1070 now is PCI:11:0:0 (which is the decimal equivalent of 0b:00.0 from the earlier step 3)
The above file defines 2 devices, the first 'nvidiaegpu' being the GTX 1070 eGPU and the second 'intel' being the Intel iGPU.  2 Server Layouts are defined, each to use the eGPU or iGPU.  Next steps would be to switch between them during boot based on if the eGPU is connected or not.

5) Now, I followed Step 4 from nu_ninja's Build guide , but also tweaked it for Arch based systems.      

      a) Create a directory called inactive in /etc/X11/xorg.conf.d/ and create a file called 01-laptop.conf

        Section "ServerFlags"                    
            Option "DefaultServerLayout" "laptop"
        EndSection    

    b) Create a script to automatically switch to eGPU GTX 1070 or Intel iGPU when the eGPU is connected or not.  This can be done by creating the following script /usr/bin/gpuswitch.sh

#!/bin/sh 

#Script should be safe as long as DIR and FILE don't point to anything valuable 
DIR=/etc/X11/xorg.conf.d 
FILE=01-laptop.conf 

TEST=$(lspci | grep -c " VGA ") 

#Check TEST against number of gpus including egpu 
if ([ $TEST -eq 2 ]); then 
   #eGPU Connected 
   echo "eGPU Connected, removing laptop config" 
   if ([ -e $DIR/$FILE ]); then 
       rm $DIR/$FILE 
   fi 
else 
   #No eGPU or unexpected number/output 
   echo "No eGPU found, switching to laptop graphics" 
   if ([ -e $DIR/$FILE ]); then 
       break 
   else 
       if ([ -e $DIR/inactive/$FILE ]); then 
           cp $DIR/inactive/$FILE $DIR/$FILE 
       fi 
   fi 
fi

 

      c)  Create a service that triggers this gpu Switch script at startup. Create a file /etc/systemd/system/gpuswitch.service

[Unit]
     Description=Script to detect and switch between Integrated Graphics and External GPU

[Service]
     ExecStart=/usr/bin/gpuswitch.sh

[Install]
     WantedBy=multi-user.target

      d)  Provide appropriate execution rights for the GPU switch service to run smoothly

sudo chmod 755 /usr/bin/gpuswitch.sh
sudo systemctl enable gpuswitch.service

6) Restart and enjoy

 

• Was unable to get the Quadro M1200 working in Laptop mode , when the eGPU 1070 is disconnected. As of now, in laptop mode the Intel iGPU is being used. Will update the above configuration once I get that working.
• KDE's KWin Compositing was dropping frames heavily and I was experiencing lots of input lag on the eGPU 1070, while everything was smooth on the Quadro M1200 and the Intel iGPU, even on the same NVidia driver.  The silver bullet to fix this issue turned out to be setting  ‘export KWIN_COMPOSE=O2ES’ in /etc/profile.d/kwin.sh during KDE startup.
• Bumblebee never worked for me, even with Intel iGPU and Quadro M1200 dGPU. So, I always used Prime. So, never bothered to test this eGPU stuff with Bumblebee