Zoltán Böszörményi authored Jul 08, 2021 and Povilas Kanapickas committed Jul 30, 2021

This allows e.g. an UDL device (driven by llvmpipe) to be automatically
set up with GPU acceleration via reverse PRIME.

The result is e.g.:

  # DISPLAY=:0.2 xrandr --listproviders
  Providers: number : 2
  Provider 0: id: 0xec cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 1 outputs: 1 associated providers: 1 name:modesetting
  Provider 1: id: 0x12c cap: 0xb, Source Output, Sink Output, Sink Offload crtcs: 2 outputs: 2 associated providers: 1 name:Intel

Signed-off-by: Zoltán Böszörményi <zboszor@gmail.com>