Re: genfb(4) vs. screen types and font changes/uses

[RVP <rvp%SDF.ORG@localhost>]

On Tue, 25 Aug 2026, Greg A. Woods wrote:

> But again, genfb(4) shouldn't be switching the screen resolution -- it
> should simply be discovering what resolution the bootloader changed it
> to!

It doesn't, and it can't. genfb(4) and vesafb just provide access to a
dumb, linear framebuffer. All resolution changes are are done by the BIOS via
the bootloader. The kernel, ie. genfb(4), can't do this.

> It shouldn't be doing any font switching either.

Well, I prefer the larger fonts myself, but, if you don't want any font change,
just compile only a single font into the kernel.

> I'm betting this part of the reason, if not the whole reason, that
> genfb(4) causes a scrambled mess of bits on the screen on my macbook-air
> when it attaches (thus so far making testing or further development on
> the macbook impossible).

No, that's due to a bootloader bug (which triggers on Macs--which present a
single resolution). I have a fix--file a PR soon after I read the UEFI stds
a bit more.

-RVP