> Date: Tue, 27 Jan 2026 12:05:01 +0100
> From: Kirill A. Korinsky <kirill@korins.ky>
> 
> On Tue, 27 Jan 2026 10:21:02 +0100,
> Crystal Kolipe <kolipe.c@exoticsilicon.com> wrote:
> > 
> > On Tue, Jan 27, 2026 at 03:21:36AM +0100, Kirill A. Korinsky wrote:
> > > The fallback forces VGA text mode even when the VGA probe fails, that
> > > guaranteeing an early console, so boot can proceed even if GOP is absent
> > > and no GPU driver is available.
> > 
> > With this patch, the kernel will be writing to memory locations and I/O ports
> > that are traditionally associated with VGA hardware, despite no VGA hardware
> > (or emulation thereof), necessarily being present.
> > 
> > Whilst it fixes your machine, how confident can we be that this is harmless on
> > others?
> > 
> > It's perfectly valid to have no graphics hardware at all and run entirely from
> > a serial console, so this could plausibly break machines that are currently
> > working just fine.
> > 
> 
> Well, here my assumption that on amd64, both the VGA legacy memory region
> and I/O ports is still reserved and not used.
> 
> This machine has such region reserved, but you raised a good question: can
> it be reused in the future for something else? My bet here that it will be
> reserved for compatiblity, and this is quite small memory to be reused
> anywere these days.
> 
> I only can think only about a check that goes by bios_memmap and checks that
> this memory is actually reserved (it's true on this), but I have no idea how
> to check that it isn't used for anything other that trivial BIOS_MAP_RES.

Instead of using the VGA legacy memory region we could maybe just
allocate a dummy framebuffer?