[X-Cubed]

They mentioned that the display output is currently using a framebuffer provided by the boot loader. I suspect when the DCP is initialized, the screen starts displaying a different framebuffer provided by the DCP, so if it was just used for brightness the screen would go blank.

[Wowfunhappy]

Could you switch it back afterwards though? Having it temporarily blank to switch brightness doesn't seem so awful.

[zamadatix]

Even if you could I don’t think the GPU stuff is far enough behind to really worry about it.