[coyotos-dev] The joys of BIOS bugs

[Jonathan S. Shapiro]

Over the past three days I have been fighting some delightful BIOS bugs.
The most recent one is an inconsistency in the treatment of physical
memory regions. Today, I saw a BIOS claim (via the memory region list)
that [0-0x9F400] was RAM and [0x9F400-0x100000] (or some such) was
reserved for ROMs. The self-same BIOS identified the region
[0x9F000-0x9FC00] as the extended BIOS data area.

The left ROM author apparently does not speak to the right ROM author.

The same BIOS, by the way, had an ACPI table that failed to checksum.

The former bug is obscure -- there is legitemate ambiguity about what
the two subsystems are supposed to do, and we noticed it because we try
to fill in missing pieces like this where we know about them.

But an ACPI table that fails to checksum is just a bug, plain and
simple.


shap