From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
The cpufreq policy notifier in the ACPI processor driver may as
well be registered before the driver itself, which causes
acpi_processor_cpufreq_init to be true (unless the notifier
registration fails, which is unlikely at that point) when the
ACPI CPU thermal cooling devices are registered, so the
processor_get_max_state() result does not change while
acpi_processor_driver_init() is running.
Change the ordering in acpi_processor_driver_init() accordingly
to prevent the max_state value from remaining 0 permanently for all
ACPI CPU cooling devices due to setting acpi_processor_cpufreq_init
too late. [Note that processor_get_max_state() may still return
different values at different times after this change, depending on
the cpufreq driver registration time, but that issue needs to be
addressed separately.]
Fixes: a365105c685c("thermal: sysfs: Reuse cdev->max_state")
Reported-by: Wang, Quanxian <quanxian.wang@xxxxxxxxx>
Link: https://lore.kernel.org/linux-pm/53ec1f06f61c984100868926f282647e57ecfb2d.camel@xxxxxxxxx/
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Tested-by: Zhang Rui <rui.zhang@xxxxxxxxx>
Reviewed-by: Zhang Rui <rui.zhang@xxxxxxxxx>
---
v2 -> v3: Add tags from Rui.
v1 -> v2: Expand changelog to explain that this particular patch addresses
part of the issue.
---
drivers/acpi/processor_driver.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
Index: linux-pm/drivers/acpi/processor_driver.c
===================================================================
--- linux-pm.orig/drivers/acpi/processor_driver.c
+++ linux-pm/drivers/acpi/processor_driver.c
@@ -263,6 +263,12 @@ static int __init acpi_processor_driver_
if (acpi_disabled)
return 0;
+ if (!cpufreq_register_notifier(&acpi_processor_notifier_block,
+ CPUFREQ_POLICY_NOTIFIER)) {
+ acpi_processor_cpufreq_init = true;
+ acpi_processor_ignore_ppc_init();
+ }
+
result = driver_register(&acpi_processor_driver);
if (result < 0)
return result;
@@ -276,12 +282,6 @@ static int __init acpi_processor_driver_
cpuhp_setup_state_nocalls(CPUHP_ACPI_CPUDRV_DEAD, "acpi/cpu-drv:dead",
NULL, acpi_soft_cpu_dead);
- if (!cpufreq_register_notifier(&acpi_processor_notifier_block,
- CPUFREQ_POLICY_NOTIFIER)) {
- acpi_processor_cpufreq_init = true;
- acpi_processor_ignore_ppc_init();
- }
-
acpi_processor_throttling_init();
return 0;
err:
