ACPI / PM: Leave Bus Master Arbitration enabled for suspend/resume
authorJonathan Nieder <jrnieder@gmail.com>
Sun, 8 Jul 2012 19:55:14 +0000 (21:55 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 16 Jul 2012 16:04:37 +0000 (09:04 -0700)
commitd63d3985914e19816e9c19faab7abe336d80be89
tree175210571a40c98ac2962fdb8c5ed18f59ce08f8
parent76c6b958de9e72947ef08b1c9509f094c34abd8f
ACPI / PM: Leave Bus Master Arbitration enabled for suspend/resume

commit dc332fdf9f373a87b1e2f423b5b004b2a3c37e1a upstream.

This is an old suspend/resume lockup fix:

commit 2780cc4660e1
Author: Len Brown <len.brown@intel.com>
Date:   Thu Dec 23 13:43:30 2004 -0500

    [ACPI] Fix suspend/resume lockup issue
    by leaving Bus Master Arbitration enabled.
    The ACPI spec mandates it be disabled only for C3.

    http://bugzilla.kernel.org/show_bug.cgi?id=3599

Signed-off-by: David Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
The bug snuck back in in commit 2feec47d4c5f (ACPICA: ACPI 5: Support
for new FADT SleepStatus, SleepControl registers, 2012-02-14),
presumably by copy/pasting a copy of the code without that fix for the
legacy case.

On affected machines, after that commit, the machine locks up hard on
resume from suspend.  The same fix as seven years ago still works.

Addresses <https://bugzilla.kernel.org/show_bug.cgi?id=43641>.

Reported-bisected-and-tested-by: Octavio Alvarez <alvarezp@alvarezp.com>
Reported-by: Adrian Knoth <adi@drcomp.erfurt.thur.de>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/acpi/acpica/hwsleep.c