[R_mand]

“The two processors communicate over a set of interfaces we call the Interconnect: SPI carries the framebuffer to the MCU for display output”

Even with peripheral DMA this idea sounds terrifying.

[bradfa]

It's a pretty normal thing to do for small LCD screens. Linux has had SPI framebuffer support via fbtft subsystem (in staging tree now, previously was out of tree) for well over a decade. It works quite well.