From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> After a previous change, cpuidle_play_dead(), which is the only caller of idle state :enter_dead() callbacks, ignores their return values, so they may as well be void. Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> --- v1 -> v2: New patch Interestingly enough, the only user of :enter_dead() idle state callbacks in the current mainline turns out to be ACPI idle. --- drivers/acpi/processor_idle.c | 7 ++----- include/linux/cpuidle.h | 2 +- 2 files changed, 3 insertions(+), 6 deletions(-) Index: linux-pm/include/linux/cpuidle.h =================================================================== --- linux-pm.orig/include/linux/cpuidle.h +++ linux-pm/include/linux/cpuidle.h @@ -61,7 +61,7 @@ struct cpuidle_state { struct cpuidle_driver *drv, int index); - int (*enter_dead) (struct cpuidle_device *dev, int index); + void (*enter_dead) (struct cpuidle_device *dev, int index); /* * CPUs execute ->enter_s2idle with the local tick or entire timekeeping Index: linux-pm/drivers/acpi/processor_idle.c =================================================================== --- linux-pm.orig/drivers/acpi/processor_idle.c +++ linux-pm/drivers/acpi/processor_idle.c @@ -578,7 +578,7 @@ static void __cpuidle acpi_idle_do_entry * @dev: the target CPU * @index: the index of suggested state */ -static int acpi_idle_play_dead(struct cpuidle_device *dev, int index) +static void acpi_idle_play_dead(struct cpuidle_device *dev, int index) { struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu); @@ -591,11 +591,8 @@ static int acpi_idle_play_dead(struct cp else if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) { io_idle(cx->address); } else - return -ENODEV; + return; } - - /* Never reached */ - return 0; } static __always_inline bool acpi_idle_fallback_to_c1(struct acpi_processor *pr)