[coreboot] Holding the s2895 in reset powers off the machine

Myles Watson mylesgw at gmail.com
Wed Jul 8 15:52:09 CEST 2009

On Wed, Jul 8, 2009 at 1:13 AM, Rudolf Marek <r.marek at assembler.cz> wrote:

> Hi,
> Please tell what superios are there. The pwrgood is sometimes involved. It
> looks like a SIO thingie.

smsc lpc47b397.

On Tue, Jul 7, 2009 at 6:17 PM, Carl-Daniel Hailfinger <
c-d.hailfinger.devel.2006 at gmx.net> wrote:

> I have no idea if the reset button directly triggers a reset line or
> something similar on the processor, but it would be interesting to know:
> 1. Does the power off also happen if you hold reset after the machine
> has already been booted? (Do n seconds of reset always trigger a poweroff?)
No.  After a few seconds of booting you can hold it in reset as long as you
want.  Since there is no output (no post codes either), I haven't been able
to narrow it down.

What I'm hoping is that it is some setting that can be saved by the device
for the next boot.  Otherwise I have to figure out a workaround, since I
can't access the SuperIO before HT is initialized, and I need to hold the
board in reset before HT is initialized.

> 2. Which part of the board reacts to the held reset line and triggers
> the poweroff?
I don't know.

> 3. Is reset maybe somehow coupled to PWRGOOD and holding down reset is
> perceived as electrical problem of the power supply?
Since #1 is no, I don't think so.

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