[Linux] Unable to offload Dota2 to eGPU on laptop with integrated + dedicated Nvidia graphics

[mikoff]

Your system information

• System information from steam (Steam -> Help -> System Information) in a gist: https://gist.github.com/mikoff/38b1b25cf646f1815ffafb59ac0884f5
• Have you checked for system updates?: Yes
• Are you using the latest stable video driver available for your system? Yes, nvidia-535.
• Have you verified the game files?: Yes

Please describe your issue in as much detail as possible:

I have a laptop with:

• integrated (Intel) & dedicated GPUs (Nvidia MX150);
• eGPU (Nvidia RX2070) connected to the laptop through Thunderbolt.

I can successfully offload all the apps to eGPU (e.g. glxgears) and see that the process is really processed on this (using nvidia-smi, I see that the eGPU is actually loaded).

However, it is not the case for Dota2 or other steam-games. They, nevertheless, are calculated on internal GPU of the laptop (MX150).

Steps for reproducing this issue:

1. Prepend the following parameters to the Dota2 or steam client: __NV_PRIME_RENDER_OFFLOAD=1 __NV_PRIME_RENDER_OFFLOAD_PROVIDER=NVIDIA-G1 __GLX_VENDOR_LIBRARY_NAME=nvidia %command% By doing so we say that we want our application to be uploaded to eGPU (NVIDIA-G1 in my case).

2. Start Dota2.

3. Run nvidia-smi, you will notice that the game is actually processed in "C+G" mode and offloaded to internal dedicated GPU (NVIDIA-G0, or MX150 in my case), and not to eGPU.

Note: to enable eGPU after driver install add the following line to /usr/share/X11/xorg.conf.d/10-nvidia.conf:

    Option "AllowExternalGpus" "true"

However, if I use the same env parameters to run vkcube, it works as expected, offloading it to eGPU:

[danginsburg]

Does adding -adapter 1 to the command line use the eGPU?

[mikoff]

Suprisingly, it worked out! Thanks for a hint!