In open source driver code of vc4 authored by Eric, there's something called "pixel valve". Apparently it has something to do with display output. But I would really want have more information about what exactly it is? How does it work?
https://github.com/peyo-hd/kernel_rpi/blob/vc4/arch/arm/boot/dts/bcm2708_common.dtsi
pixelvalve@7e807000 {
compatible = "brcm,bcm2835-pixelvalve2";
reg = <0x7e807000 0x100>;
interrupts = <2 10>; /* pixelvalve */
};
