[PATCH] xf86drm: add drmOpenByFB

[Simon Ser]

On Saturday, May 23, 2020 5:44 PM, Mauro Rossi <issor.oruam at gmail.com> wrote:

> OpenByFB is introduced to overcome GPU driver loading order issue
> on a device with multiple GPUs, e.g. Intel iGPU and Nvidia dGPU
> where the first drmfb kernel module loaded will become device file
> /dev/dri/card0 and the second will become /dev/dri/card1
>
> The use case is to prefer Intel iGPU over dGPU, or viceversa,
> in a deterministic and reliable manner.
>
> OpenByFB function opens the DRM device with specified fb and node type,
> thus enabling gralloc to open the correct device node of the primary fb,
> regardless of the GPU driver loading order.

"FB" is ambiguous here, because the other FB functions in this file
refer to DRM frame-buffer objects (as opposed to fbdev I believe?).