[U-Boot] [linux-sunxi] Re: [PATCH] video: add cfb console driver for sunxi

[Henrik Nordström]

mån 2014-08-04 klockan 17:05 +0200 skrev Luc Verhaegen:
> But... What do we do when u-boot sets up cfb, without setting up a
> simplefb node in the dt. Or what do we do when a simplefb node is set 
> up, but no simplefb code is included in the kernel? Well, we then either 
> need to claim the clocks, and make sure that nothing else touches the 
> memory, or we need to cleanly disable the display engine. But which do 
> we choose, do we keep the u-boot output forever, or do we sync off when 
> the kernel starts?

And what happens if we simply ignore it? Is there a risk of anything
burning beyond software repair? If not, ignore it. There is no need to
support all incompatible mixes even if it means some people will see
strange fireworks on their screens when not following the software
requirements.

It's really no different from booting a kernel with wrong dt, or using a
u-boot with wrong DRAM settings etc. An incompatible mix which is not
meant to function properly.

If you use a u-boot with this framebuffer support then you must also
either use a kernel which supports being booted in such state, or make
sure u-boot shuts things off before handing over to the kernel.

If we can handle the situation gracefully in the kernel then fine, but
it's by no means required, or even desired to spend any effort or even
any serious thoughts on before compatible setups works.

Regards
Henrik