Dustin C. Hatch
a3f5605ed4
Getting the Raspberry Pi 4 GPU and 7-inch Touch Display 2 working was quite challenging. Several kernel drivers are needed, beyond the obvious VC4 and V3D, like voltage regulators and backlight controls. Even with all the drivers enabled, I still had trouble getting `/dev/dri/card1` (the display device, as opposed to `/dev/dri/card0`, the 3D rendering device) to appear until I explicitly enabled the `vc4-kms-dsi-ili9881-7inch` device tree overlay. I am not entirely sure why this is necessary, since `display_auto_detect` supposedly should have added this overlay automatically. I am also not sure how it would work if I wanted to use an HDMI monitor instead of the DSI panel, but fortunately, for this project, that's not necessary.