Re: Raspberry Pi 4 support on 32 bit earmv7hf GENERIC kernel

[email protected] (Izumi Tsutsui) writes:

>On Raspberry Pi 4, it looks the firmware (start4.elf) dynamically
>populates /chosen node, puts "simple-framebuffer" under it, and
>then gives /chosen the non-standard compatible string "simple_bus".
>(see quoted "strings(1)" output above)


The firmware looks for a 'display0' alias and for a '/soc/fb'
entry in 'okay' state. If neither exists, it adds the
'simple-framebuffer'. The state of '/soc/fb' is normally
controlled by a device tree overlay.

So the most simple way to get a display is to restore /soc/fb.
Our platform code is then talking to the RPI firmware to get
data about the framebuffer.