This breaks the mpt(4) driver and does not let NetBSD/amd64 boot
successfully in VMware Fusion. The machine seems to emulate a
53C1030 chip, and sys/dev/pci/mpt_pci.c has:
if ((PCI_PRODUCT(pa->pa_id) == PCI_PRODUCT_SYMBIOS_1030) &&
(PCI_REVISION(pa->pa_class) < 0x08)) {
aprint_normal("%s: applying 1030 quirk\n",
mpt->sc_dev.dv_xname);
reg = pci_conf_read(pa->pa_pc, pa->pa_tag, 0x6a);
reg &= 0x8f;
pci_conf_write(pa->pa_pc, pa->pa_tag, 0x6a, reg);
}
Note the 0x6a register value in there, which will trigger the
assertion you added. I've been looking around to see if that value
is correct, but the only thing I found is the Linux code which does
the same as us (maybe we borrowed the fix from there in the first
place, or the other way around).