From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Date: Mon, 19 Aug 2013 23:42:32 +0000 (+0200)
Subject: ACPI / PM: Hold acpi_scan_lock over system PM transitions
X-Git-Tag: v3.12-rc1~178^2~16^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ad07277e82dedabacc52c82746633680a3187d25;p=pandora-kernel.git

ACPI / PM: Hold acpi_scan_lock over system PM transitions

Bad things happen if ACPI hotplug events are handled during system
PM transitions, especially if devices are removed as a result.
To prevent those bad things from happening, acquire acpi_scan_lock
when a PM transition is started and release it when that transition
is complete or has been aborted.

This fixes resume lockup on my test-bed Acer Aspire S5 that happens
when Thunderbolt devices are disconnected from the machine while
suspended.

Also fixes the analogous problem for Mika Westerberg on an
Intel DZ77RE-75K board.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
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