Hi,
+ qemu_romfile_add("etc/sercon-enable", QEMU_CFG_NOGRAPHIC, 0, 2);
Instead of looking at QEMU_CFG_NOGRAPHIC, I think the C code could check if GET_IVT(0x10).segoff == FUNC16(entry_10).segoff .
It's not that simple. We need some way to explicitly enable it, especially in case a vgabios *is* present (aka aplitmode). And this is what we've agreed on a few months back, IIRC because we don't have to extend fw_cfg that way.
Independent from that we have the question what to do by default in case no vgabios is present. IIRC by initial patch set did enable sercon in that case, but I changed it after some discussions.
Don't remember what the reason was though. Cc'ing Daniel + Paolo
cheers, Gerd