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 573b6a9..70d8a6e 100644 (file)
--- 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;
                }
        }