GMUX

[Redecorating]

Graphics Multiplexer on dual GPU models.

• [x] Read and Write to gmux ports
• [x] Backlight control
• [ ] Switching Display between GPUs
  • [x] To preserve state after resume (so you can resume properly when using the igpu!)
  • [x] At runtime with vga_switcheroo
    • [x] Make amdgpu register with vga_switcheroo
    • [x] Make intel card register with vga_switcheroo
  • [ ] Get the switched to GPU to output to the display
• [x] Interrupts
• [ ] Power up/down dGPU
  • [x] Power Down
  • [ ] #3
    • [x] mbp15,x
    • [ ] mbp16,x
  • [ ] ACPI PWRD, PWG1
• [x] Update internal documentation
• [x] Test on other T2 models once everything should be working
• [x] Ensure these changes don't cause regressions for pio and indexed models.

https://lore.kernel.org/platform-driver-x86/20230218132007.3350-1-orlandoch.dev@gmail.com/

[Redecorating]

v4: https://lore.kernel.org/platform-driver-x86/20230303112842.3094-1-orlandoch.dev@gmail.com/