[coreboot] SeaBIOS debug output
jordan.crouse at amd.com
Wed Jul 16 21:55:23 CEST 2008
On 16/07/08 12:43 -0600, Myles Watson wrote:
> On Fri, Jul 11, 2008 at 12:51 PM, Kevin O'Connor <kevin at koconnor.net> wrote:
> > On Fri, Jul 11, 2008 at 07:58:35PM +0200, Carl-Daniel Hailfinger wrote:
> >> Can seabios somehow complement x86emu as a way to let certain
> >> problematic VBIOS images run?
> > If you mean run seabios under x86emu - I'm not sure. Seabios
> > currently does its initialization in 32bit mode which x86emu may not
> > like.
> > If you mean using seabios to implement the option rom scan - then yes,
> > I think this is what Stefan suggested and Zhang Rui is working on. If
> > I understand correctly, they want to load the seabios blob into ram,
> > have seabios do its init, run the option roms, and then jump back to
> > coreboot for the rest of the boot. Presumably, coreboot would also
> > use seabios to boot the machine if the user wanted that.
> > The thing to be careful of here is making sure coreboot and seabios
> > don't stomp on each other. This may not be such a big deal - seabios
> > doesn't currently write to any ram above 1MiB - if coreboot didn't
> > write to any ram below 1MiB after launching seabios then maybe it
> > would work.
> I for one don't understand what needs to be done in coreboot after the
> option ROM scans. It seems like it would help us discuss the possible
> solutions if we could enumerate that.
> I don't think the Coreboot->SeaBIOS->Coreboot->Payload route means
> that SeaBIOS has to return to Coreboot. It seems like Coreboot can
> load whatever should come after SeaBIOS into RAM and have SeaBIOS jump
This seems like semantics to me - the jmp will be to an arbitrary
address - it doesn't really matter if it goes back to coreboot or
if it goes to the payload. If it jumped to the payload, SeaBIOS
will have to be told _where_ to jump anyway, since the payload can
live anywhere. All we really need to do is set up an interface to pass a
address to SeaBIOS, and then its up to coreboot to figure out what
they want to do after SeaBIOS is done.
Systems Software Development Engineer
Advanced Micro Devices, Inc.
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