On Mon, Sep 11, 2017 at 12:17:04PM +0200, Gerd Hoffmann wrote:
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.
Okay.
Separately, how will sercon get the serial port that it is to use?
Looking closer at patch 4 I see:
+ u16 addr = PORT_SERIAL1; + SET_LOW(sercon_port, addr);
Is the plan to pull this from a romfile so that it can be set on coreboot? If so, perhaps that functionality could be merged with "etc/sercon-enable" so that coreboot users need only set one cbfs file.
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
Okay. It would be nice to have the correct responses to 1000, 1002, 1003, and 100f even if serial output wasn't desired.
-Kevin