[coreboot] U-Boot-x86 / coreboot Integration

[Kevin O'Connor]

On Wed, May 11, 2011 at 01:27:30PM +1000, Graeme Russ wrote:
> On Wed, May 11, 2011 at 1:20 PM, Kevin O'Connor <kevin at koconnor.net> wrote:
> > On Wed, May 11, 2011 at 01:12:16PM +1000, Graeme Russ wrote:
> >> What does Linux do? i.e. if you boot Linux from coreboot, how does it
> >> output to the VGA console? I know it uses BIOS early on (before switching
> >> to protected mode) but what does it do after entering protected mode?
> >
> > In general, one enables the coreboot VGA option ROM emulation when
> > booting Linux directly from coreboot.
> 
> Yes, I understand that - But how does Linux output to the VGA console
> after switching to Protected Mode? Does it still do BIOS calls?
> 
> And what about all those Linux drivers in drivers/video - Would porting
> them (to U-Boot) elliminate the need for BIOS/Option ROMs

I'm not really sure - I'd guess it will vary significantly from card
to card and driver to driver.

I'm pretty sure you need to run the VGA option ROM if you want the
legacy text console mode.  However, some of the Linux/X11 drivers will
likely be able to get the card into graphics mode without running the
option ROM.

-Kevin