On Wed, Jul 18, 2007 at 01:15:50PM +0200, Stefan Reinauer wrote:
- Carl-Daniel Hailfinger c-d.hailfinger.devel.2006@gmx.net [070718 12:43]:
Hm. Can we abuse ACPI to do that? Like accessing SystemCMOS from a _INI function?
Possibly. But ACPI is running very early in the game. Where would we hook it up?
This would also establish ACPI as a pretty hard requirement. There should be an alternative, too.
Using ACPI here would be nicely transparent though, hiding firmware specifics in the firmware code. I like that approach.
We want to use less ACPI, not more, right? Tempting as it may be, can't we find a better way?
On Wed, Jul 18, 2007 at 04:13:24PM +0200, Carl-Daniel Hailfinger wrote:
http://www.microsoft.com/whdc/resources/respec/specs/simp_bios.mspx For the real spec, see http://www.microsoft.com/whdc/resources/respec/specs/simp_boot.mspx or google for "sbf21.doc". I have not read the real spec because I didn't want to agree to their LA.
Also see Dell's patent:
http://www.patentstorm.us/patents/6640316.html
or just google simple boot flag. This article is informative:
http://www.rtcmagazine.com/home/article.php?id=100333
It seems that the simple boot flag is merely intended to control what parts of POST is performed. Not a perfect fit for us..
Since I just discovered the Microsoft approach, I doubt we would want to invent our own mechanism.
But they are two different problems.
We could use the simple boot flag to do clever things during init (like cache a list of register writes) but normal vs. fallback is AFAIK a new concept at least in PC firmware so there's no existing mechanism that really fits.
//Peter