I believe that Venki is sending a patch to make all recent
motherboards use acpi reset by default; and I'd rather
see that kind of patch than this one.
I've had the patch below patch in acpi-test, and thus linus-next,
and -mm since Nov 2008 to change the default for
all systems w/ no issues.
Maybe I'm misremembering, but didn't we have to pull this patch after it
hit mainstream the last time?
c7ffa6c26277b403920e2255d10df849bd613380
"x86: default to reboot via ACPI"
set ACPI as the default in 2.6.28-rc1
8d00450d296dedec9ada38d43b83e79cca6fd5a3
Revert "x86: default to reboot via ACPI"
pulled it in v2.6.28-rc4
The original patch was justified by VMX support,
and the revert was in response to Andrey Borzenkov's
DMI patch to usee BIOS reset on his Toshiba Porgege 4000:
http://lkml.org/lkml/2008/10/31/242
The Toshiba Portege 4000 shipped in early 2002.
The patch to restore ACPI reset to default has been in Linux-next
(with occasional drops) since the day it was dropped from 2.6.28-rc4.
As we have an existence proof, I have no doubt that using
ACPI reset by default will un-earth some regressions. However,
my guess is that the DMI list of old machines that will fail
with ACPI reset will be smaller than by the DMI list of
brand-new machines that will fail without ACPI reset.
We couuld use a DMI year cut-off as we do with
ACPI itself CONFIG_ACPI_BLACKLIST_YEAR, though that
doesn't work on systems that don't have DMI...
If I were to propose a year, I'd say 2006 and newer,
since XP was "Windows 2006".