From: Linus Torvalds <torvalds@g5.osdl.org>
Date: Fri, 18 Nov 2005 15:29:51 +0000 (-0800)
Subject: Fix ACPI processor power block initialization
X-Git-Tag: v2.6.15-rc2~36
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2203d6ed448ff3b777ee6bb614a53e686b483e5b;p=linux-2.6

Fix ACPI processor power block initialization

Properly clear the memory, and set "pr->flags.power" only if a C2 or
deeper state is valid (to make the code match both the comment and
previous behaviour).

This fixes a boot-time lockup reported by Maneesh Soni when using
"maxcpus=1".

Acked-by: Maneesh Soni <maneesh@in.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 573b6a97bb..70d8a6ec09 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -514,8 +514,6 @@ static int acpi_processor_set_power_policy(struct acpi_processor *pr)
 
 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
 {
-	int i;
-
 	ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_fadt");
 
 	if (!pr)
@@ -524,8 +522,7 @@ static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
 	if (!pr->pblk)
 		return_VALUE(-ENODEV);
 
-	for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++)
-		memset(pr->power.states, 0, sizeof(struct acpi_processor_cx));
+	memset(pr->power.states, 0, sizeof(pr->power.states));
 
 	/* if info is obtained from pblk/fadt, type equals state */
 	pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
@@ -555,13 +552,9 @@ static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
 
 static int acpi_processor_get_power_info_default_c1(struct acpi_processor *pr)
 {
-	int i;
-
 	ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_default_c1");
 
-	for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++)
-		memset(&(pr->power.states[i]), 0,
-		       sizeof(struct acpi_processor_cx));
+	memset(pr->power.states, 0, sizeof(pr->power.states));
 
 	/* if info is obtained from pblk/fadt, type equals state */
 	pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
@@ -873,7 +866,8 @@ static int acpi_processor_get_power_info(struct acpi_processor *pr)
 	for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
 		if (pr->power.states[i].valid) {
 			pr->power.count = i;
-			pr->flags.power = 1;
+			if (pr->power.states[i].type >= ACPI_STATE_C2)
+				pr->flags.power = 1;
 		}
 	}