[coreboot] Serial Console only starts after reset

Joseph Smith joe at settoplinux.org
Tue Jun 15 16:28:51 CEST 2010

On Tue, 15 Jun 2010 16:16:46 +0200, Stefan Reinauer <stepan at coresystems.de>
> On 6/15/10 4:07 PM, Joseph Smith wrote:
>> When
>> I cold boot it, if I hit the reset button before Linux starts, it
> restarts
>> with coreboot serial console just fine.
> Hm...
> Maybe 0x2e/0x4e are mapped to LPC after the SuperIO is configured (and
> that mapping survives a reset)... that would be a southbridge init issue.
Hmm, This is interesting. The first time I booted it, I had copied romstage
from another board that had:


And I got coreboot serial console (early_serial) just fine but when it came
to detecting and inializing the superio, I got all kinds of errors from
coreboot about device not found.

So I changed it to 0x2e as described in the datasheet and detected with
superiotool(vendor bios), and that is when this problem started. But now
coreboot is happy, detects the device and the resource allocator is happy,
I just do not get early_serial on cold boot.

This is weird!

> Or, the hardware has to stabilize after power on before you can
> configure the SuperIO.

Joseph Smith

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