Commit f694481b authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

ACPI: processor: Rescan "dead" SMT siblings during initialization 



Make acpi_processor_driver_init() call arch_cpu_rescan_dead_smt_siblings(),
via a new wrapper function called acpi_idle_rescan_dead_smt_siblings(),
after successfully initializing the driver, to allow the "dead" SMT
siblings to go into deep idle states, which is necessary for the
processor to be able to reach deep package C-states (like PC10) going
forward, so that power can be reduced sufficiently in suspend-to-idle,
among other things.

However, do it only if the ACPI idle driver is the current cpuidle
driver (otherwise it is assumed that another cpuidle driver will take
care of this) and avoid doing it on architectures other than x86.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Link: https://patch.msgid.link/2005721.PYKUYFuaPT@rjwysocki.net
parent a430c11f

drivers/acpi/internal.h

+6 −0
Original line number Diff line number Diff line
@@ -175,6 +175,12 @@ bool processor_physically_present(acpi_handle handle); 
static inline void acpi_early_processor_control_setup(void) {}

#endif



#ifdef CONFIG_ACPI_PROCESSOR_CSTATE

void acpi_idle_rescan_dead_smt_siblings(void);

#else

static inline void acpi_idle_rescan_dead_smt_siblings(void) {}

#endif



/* --------------------------------------------------------------------------

                                  Embedded Controller

   -------------------------------------------------------------------------- */

drivers/acpi/processor_driver.c

+3 −0
Original line number Diff line number Diff line
@@ -279,6 +279,9 @@ static int __init acpi_processor_driver_init(void) 
	 * after acpi_cppc_processor_probe() has been called for all online CPUs

	 */

	acpi_processor_init_invariance_cppc();



	acpi_idle_rescan_dead_smt_siblings();



	return 0;

err:

	driver_unregister(&acpi_processor_driver);

drivers/acpi/processor_idle.c

+8 −0
Original line number Diff line number Diff line
@@ -24,6 +24,8 @@ 
#include <acpi/processor.h>

#include <linux/context_tracking.h>



#include "internal.h"



/*

 * Include the apic definitions for x86 to have the APIC timer related defines

 * available also for UP (on SMP it gets magically included via linux/smp.h).
@@ -55,6 +57,12 @@ struct cpuidle_driver acpi_idle_driver = { 
};



#ifdef CONFIG_ACPI_PROCESSOR_CSTATE

void acpi_idle_rescan_dead_smt_siblings(void)

{

	if (cpuidle_get_driver() == &acpi_idle_driver)

		arch_cpu_rescan_dead_smt_siblings();

}



static

DEFINE_PER_CPU(struct acpi_processor_cx * [CPUIDLE_STATE_MAX], acpi_cstate);