Monterey (and probably Big Sur) compatibility issue - fails eGPU detection

[eweiman]

Attempting to run the script as-is fails on 12.3.1, another mac on 11.6.5 (that doesn't have eGPU) also fails to have any output from this command.
Deploying a workaround allows it to function correctly to set / probe the eGPU preferences on the apps.

eweiman@eweiman-mbp-osx ~ % sw_vers
ProductName:	macOS
ProductVersion:	12.3.1
BuildVersion:	21E258

This line tries to use ioreg to determine if the eGPU is connected on Mojave and later.
https://github.com/mayankk2308/set-egpu/blob/master/set-eGPU.sh#L159

# Check eGPU presence for Mojave+
check_egpu_presence() {
  (( ${IS_HIGH_SIERRA} == 1 )) && return
  EGPU_VENDOR="$(ioreg -n display@0 | grep \"vendor-id\" | cut -d "=" -f2 | sed 's/ <//' | sed 's/>//' | cut -c1-4 | sed -E 's/^(.{2})(.{2}).*$/\2\1/')"
  [[ -z "${EGPU_VENDOR}" ]] && echo -e "\nExternal GPU must be plugged in for ${BOLD}set-eGPU${NORMAL} on macOS 10.14+.\n" && exit
}

however this has zero output:

%  ioreg -n display@0 | grep \"vendor-id\" | cut -d "=" -f2 | sed 's/ <//' | sed 's/>//' | cut -c1-4 | sed -E 's/^(.{2})(.{2}).*$/\2\1/'|wc -l
       0

As a workaround I changed this line to read:
EGPU_VENDOR=AMD
Which then allowed me to run this just fine.

You'd probably be better off using system_profiler for this kind of check.

Example output (which can be quite verbose with many displays connected):

eweiman@eweiman-mbp-osx ~ % system_profiler SPDisplaysDataType
2022-05-02 11:14:58.005 system_profiler[87107:1263592] Device PreExisted [00000001000006c6] AMD Radeon RX 580
2022-05-02 11:14:58.006 system_profiler[87107:1263592] Device PreExisted [0000000100000622] Intel Iris Pro Graphics
2022-05-02 11:14:58.006 system_profiler[87107:1263592] Synchronize with Metal initialization
2022-05-02 11:15:01.012 system_profiler[87107:1263592] Can't find (Metal) name, location, locationNumber, maxTransferRate
2022-05-02 11:15:01.013 system_profiler[87107:1263592] Synchronize with Metal initialization
2022-05-02 11:15:04.013 system_profiler[87107:1263592] Can't find (Metal) name, location, locationNumber, maxTransferRate
2022-05-02 11:15:04.043 system_profiler[87107:1263592] Synchronize with Metal initialization
2022-05-02 11:15:07.044 system_profiler[87107:1263592] Can't find (Metal) name, location, locationNumber, maxTransferRate
2022-05-02 11:15:07.045 system_profiler[87107:1263592] Synchronize with Metal initialization
2022-05-02 11:15:10.053 system_profiler[87107:1263592] Can't find (Metal) name, location, locationNumber, maxTransferRate
Graphics/Displays:

    Intel Iris Pro Graphics 5200:

      Chipset Model: Intel Iris Pro Graphics 5200
      Type: GPU
      Bus: Built-In
      VRAM (Dynamic, Max): 1536 MB
      Vendor: Intel
      Device ID: 0x0d26
      Revision ID: 0x0008
      Metal Family: Supported, Metal GPUFamily macOS 1
      Displays:
        Color LCD:
          Display Type: Built-In Retina LCD
          Resolution: 2880 x 1800 Retina
          Framebuffer Depth: 24-Bit Color (ARGB8888)
          Mirror: Off
          Online: Yes
          Automatically Adjust Brightness: Yes
          Connection Type: Internal

    Radeon RX 580:

      Chipset Model: Radeon RX 580
      Type: External GPU
      Bus: PCIe
      PCIe Lane Width: x4
      VRAM (Total): 4 GB
      Vendor: AMD (0x1002)
      Device ID: 0x67df
      Revision ID: 0x00e7
      Metal Family: Supported, Metal GPUFamily macOS 1
      GPU is Removable: Yes
      Displays:
        DELL P2217H:
          Resolution: 1920 x 1080 (1080p FHD - Full High Definition)
          UI Looks like: 1920 x 1080 @ 60.00Hz
          Framebuffer Depth: 30-Bit Color (ARGB2101010)
          Display Serial Number: 4RDG97C71234
          Main Display: Yes
          Mirror: Off
          Online: Yes
          Rotation: Supported

You might be able to just grep for "External GPU" in this case, or if you really need the vendor info you could get that as well, however I don't see a reason to get that specific.

eweiman@eweiman-mbp-osx ~ % system_profiler SPDisplaysDataType 2>/dev/null|grep External
      Type: External GPU