[coreboot] motherboards support SMM

Scott Duplichan scott at notabs.org
Sat Oct 23 23:51:31 CEST 2010

-----Original Message-----
From: coreboot-bounces at coreboot.org [mailto:coreboot-bounces at coreboot.org] On Behalf Of Keith Hui
Sent: Saturday, October 23, 2010 04:16 PM
To: coreboot at coreboot.org
Subject: Re: [coreboot] motherboards support SMM

]> Why are you so interested in SMM?
]> As I mentioned above, coreboot will avoid using SMM unless it is a
]> requirement for a particular platform.
]> If you want to add SMM to a platform where it is not used currently
]> (and thus not required for coreboot) then it seems that you you have
]> a lot of research and development ahead of you.
]Is it possible to have ACPI support for a board without SMM?

Hello Keith,

The answer is yes. I don't use SMI yet I have Windows 7 working well.
The main ACPI use for SMI is to let the OS tell a BIOS to switch power
management interrupts from SMI mode to SCI mode. Coreboot solves this
problem by enabling SCI handling of power management interrupts by
default. What is the disadvantage to this method? In other words, what
is sacrificed by not using SMI? It is the loss is power management features
for non-ACPI operating systems. An example is power button control for
non-ACPI aware operating systems. If I boot DOS using coreboot+seabios,
the power button doesn't work (except for the 4 second override). With
a traditional BIOS, SMI handling of the power management event triggered
by the power button allows it to work in this case.


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