cpuidle acpi driver: fix oops on AC<->DC
cpuidle and acpi driver interaction bug with the way cpuidle_register_driver()
is called. Due to this bug, there will be oops on
AC<->DC on some systems, where they support C-states in one DC and not in AC.
The current code does
ON BOOT:
Look at CST and other C-state info to see whether more than C1 is
supported. If it is, then acpi processor_idle does a
cpuidle_register_driver() call, which internally enables the device.
ON CST change notification (AC<->DC) and on suspend-resume:
acpi driver temporarily disables device, updates the device with
any new C-states, and reenables the device.
The problem is is on boot, there are no C2, C3 states supported and we skip
the register. Later on AC<->DC, we may get a CST notification and we try
to reevaluate CST and enabled the device, without actually registering it.
This causes breakage as we try to create /sys fs sub directory, without the
parent directory which is created at register time.
Thanks to Sanjeev for reporting the problem here.
http://bugzilla.kernel.org/show_bug.cgi?id=10394
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 2dd2c1f..556ee15 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -1669,6 +1669,7 @@
return -EINVAL;
}
+ dev->cpu = pr->id;
for (i = 0; i < CPUIDLE_STATE_MAX; i++) {
dev->states[i].name[0] = '\0';
dev->states[i].desc[0] = '\0';
@@ -1738,7 +1739,7 @@
int acpi_processor_cst_has_changed(struct acpi_processor *pr)
{
- int ret;
+ int ret = 0;
if (boot_option_idle_override)
return 0;
@@ -1756,8 +1757,10 @@
cpuidle_pause_and_lock();
cpuidle_disable_device(&pr->power.dev);
acpi_processor_get_power_info(pr);
- acpi_processor_setup_cpuidle(pr);
- ret = cpuidle_enable_device(&pr->power.dev);
+ if (pr->flags.power) {
+ acpi_processor_setup_cpuidle(pr);
+ ret = cpuidle_enable_device(&pr->power.dev);
+ }
cpuidle_resume_and_unlock();
return ret;
@@ -1813,7 +1816,6 @@
if (pr->flags.power) {
#ifdef CONFIG_CPU_IDLE
acpi_processor_setup_cpuidle(pr);
- pr->power.dev.cpu = pr->id;
if (cpuidle_register_device(&pr->power.dev))
return -EIO;
#endif
@@ -1850,8 +1852,7 @@
return 0;
#ifdef CONFIG_CPU_IDLE
- if (pr->flags.power)
- cpuidle_unregister_device(&pr->power.dev);
+ cpuidle_unregister_device(&pr->power.dev);
#endif
pr->flags.power_setup_done = 0;