[coreboot] FW: PCI BIOS Extension ROM in v3

Myles Watson myles at pel.cs.byu.edu
Tue Jan 22 19:29:06 CET 2008

> On 22.01.2008 18:59, Myles Watson wrote:
> > Coreboot v3 refuses to initialize the VGA in QEMU because the PCI device
> > ID's are mismatched.
> >
> > It turns out that the header has been overwritten by a copyright string,
> so
> > that v3 is following a bad pointer into the ROM looking for the PCI
> device
> > IDs and not finding it.  Coreboot v2 still successfully initializes the
> > because it skips the vendor check.
> >
> > The question is if we should make the vendor check a warning instead of
> > failing.  I realize that the right thing to do is fix the ROM, but there
> may
> > be other broken ROMs as well.
> >
> I'd say we refuse to execute the ROM in v3. If the ROM is broken, we
> have no way to determine how broken it is. Unconditional execution may
> prevent booting the machine, thereby forcing an out-of-system flash of
> coreboot with ROM execution disabled.
> How many ROMs of real hardware are broken that way? If their number is
> close to zero, printing a scary warning message will be best. If there
> is a large number of such broken ROMs, we can make execution dependent
> on some NVRAM setting, which will refuse execution after NVRAM clear.

I have no idea how many there are.

> Do you know which versions of Qemu ship the broken ROM? Is there already
> a patch for it?

0.9.0, 0.9.1
I haven't seen a patch for it, or anyone else complaining about it.  It made
me wonder if Coreboot is the only thing that cares if the ROM is broken.


Carl-Daniel: I forgot to CC the list last time.

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