From: Andreas Mohr <[andi@rhlx01.fht-esslingen.de]>
Date: Mon, 26 Jun 2006 19:58:00 +0000 (-0400)
Subject: ACPI: restore comment justifying 'extra' P_LVLx access
X-Git-Tag: v2.6.18-rc1~257^2~6^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b488f02156d3deb08f5ad7816d565c370a8cc6f1;p=pandora-kernel.git

ACPI: restore comment justifying 'extra' P_LVLx access

While trying to look for superfluous I/O accesses that can be optimized
away, I stumbled upon this ACPI sleep I/O access and couldn't figure out
why the hell this dummy op was necessary.
After more than one hour of internet research, I had collected a sufficient
number of documents (among those very old kernel versions) that finally
told me what this dummy read was about: STPCLK# doesn't get asserted in time
on (some) chipsets, which is why we need to have a dummy I/O read to delay
further instruction processing until the CPU is fully stopped.

Signed-off-by: Andreas Mohr <andi@lisas.de>
Signed-off-by: Len Brown <len.brown@intel.com>
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