From: Lv Zheng <lv.zheng@intel.com>
Date: Sat, 8 Jun 2013 00:59:18 +0000 (+0000)
Subject: ACPICA: Do not use extended sleep registers unless HW-reduced bit is set
X-Git-Tag: firefly_0821_release~6453^2~1556
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=22a5fdfc36cd18abfd421699e9076307fa54dae4;p=firefly-linux-kernel-4.4.55.git

ACPICA: Do not use extended sleep registers unless HW-reduced bit is set

commit 7cec7048fe22e3e92389da2cd67098f6c4284e7f upstream.

Previous implementation incorrectly used the ACPI 5.0 extended
sleep registers if they were simply populated. This caused
problems on some non-HW-reduced machines. As per the ACPI spec,
they should only be used if the HW-reduced bit is set.  Lv Zheng,
ACPICA BZ 1020.

Reported-by: Daniel Rowe <bart@fathom13.com>
References: https://bugzilla.kernel.org/show_bug.cgi?id=54181
References: https://bugs.acpica.org/show_bug.cgi?id=1020
Bisected-by: Brint E. Kriebel <kernel@bekit.net>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/acpi/acpica/hwxfsleep.c b/drivers/acpi/acpica/hwxfsleep.c
index 35eebdac0f9d..09b06e2feff8 100644
--- a/drivers/acpi/acpica/hwxfsleep.c
+++ b/drivers/acpi/acpica/hwxfsleep.c
@@ -240,12 +240,14 @@ static acpi_status acpi_hw_sleep_dispatch(u8 sleep_state, u32 function_id)
 	    &acpi_sleep_dispatch[function_id];
 
 #if (!ACPI_REDUCED_HARDWARE)
-
 	/*
 	 * If the Hardware Reduced flag is set (from the FADT), we must
-	 * use the extended sleep registers
+	 * use the extended sleep registers (FADT). Note: As per the ACPI
+	 * specification, these extended registers are to be used for HW-reduced
+	 * platforms only. They are not general-purpose replacements for the
+	 * legacy PM register sleep support.
 	 */
-	if (acpi_gbl_reduced_hardware || acpi_gbl_FADT.sleep_control.address) {
+	if (acpi_gbl_reduced_hardware) {
 		status = sleep_functions->extended_function(sleep_state);
 	} else {
 		/* Legacy sleep */