[PATCH 3.16.y-ckt 019/180] cpuidle: ACPI: do not overwrite name and description of C0

From: Luis Henriques
Date: Thu May 07 2015 - 06:46:38 EST


3.16.7-ckt11 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Thomas Schlichter <thomas.schlichter@xxxxxx>

commit c7e8bdf5872c5a8f5a6494e16fe839c38a0d3d3d upstream.

Fix a bug that leads to showing the name and description of C-state C0
as "<null>" in sysfs after the ACPI C-states changed (e.g. after AC->DC
or DC->AC
transition).

The function poll_idle_init() in drivers/cpuidle/driver.c initializes the
state 0 during cpuidle_register_driver(), so we better do not overwrite it
again with '\0' during acpi_processor_cst_has_changed().

Signed-off-by: Thomas Schlichter <thomas.schlichter@xxxxxx>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
drivers/acpi/processor_idle.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 17f9ec501972..fd8496a92b45 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -962,7 +962,7 @@ static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
return -EINVAL;

drv->safe_state_index = -1;
- for (i = 0; i < CPUIDLE_STATE_MAX; i++) {
+ for (i = CPUIDLE_DRIVER_STATE_START; i < CPUIDLE_STATE_MAX; i++) {
drv->states[i].name[0] = '\0';
drv->states[i].desc[0] = '\0';
}
--
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