Detecting gpu from egpu-switcher conf file instead of Xorg file

[Astaoth]

Hi !

Some context :
I have a laptop with an Intel GPU and a Nvidia Quadro. It works fine, if I want to run programs on my nvidia card I can use prime-run, else they will be executed on the Intel GPU.
Now, I would like to use a eGPU. With egpu-switcher, the generated Xorg configuration put the eGPU as the Sink device and the Intel GPU as a secondary GPU. Which means the X programs are run by default on the eGPU, and the laptop screen (which is connected to the Intel GPU) has many tearing problems.
I fixed this with a custom xorg.conf.egpu with defines the Intel GPU as the main one, and in order to run programs on the eGPU I have to prefix them with a DRI_PRIME=1. This way, with a eGPU connected I have more or less the same behaviour : for running programs on the most performant GPU I have to execute them with a prefixe (either DRI_PRIME=1 or prime-run), and without it they will be run on the Intel GPU.
But with this xorg.conf.egpu file, the eGPU detection doesn't work because I have the 3 PCI GPU card in it, and the first one is the Intel GPU.

The issue
However, since a egpu-switcher config doesn't override the xorg.conf files which allow me to have my custom conf, and has its own conf file with the eGPU PCI Bus, would it be possible to replace the line 134 "declare egpu_pci_id=$(cat $xfile_egpu | grep -Ei "BusID" | grep -oEi '[0-9]+:[0-9]+:[0-9]+')" by "declare egpu_pci_id=$(cat $config_file | grep "external_gpu" | cut -d '=' -f2" ?
With this, it will allow users to have a custom xorg.conf.egpu file with a working eGPU detection.

Thank you

System informations :

• Did you install egpu-switcher via ppa or via git + make : egpu-switcher is installed from AUR (so it's kind of git+make)
• What Linux distribution (+ version) are you using : Archlinux
• What brand / model is your laptop : Dell precision 7510 with NVidia Quadro
• What brand / model is your GPU (+ enclosure) : AMD RX580 + Akitio Node
• What drivers (+ version) are you using : latest amdgpu and nvidia 470
• What Desktop-Environment do you use (+ Display-Manager) : Xorg with FVWM (no DE)