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Commit d6f346f2 authored by Daniel Lezcano's avatar Daniel Lezcano Committed by Rafael J. Wysocki
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cpuidle: improve governor Kconfig options 



Each governor is suitable for different kernel configurations: the menu
governor suits better for a tickless system, while the ladder governor fits
better for a periodic timer tick system.

The Kconfig does not allow to [un]select a governor, thus both are compiled in
the kernel but the init order makes the menu governor to be the last one to be
registered, so becoming the default. The only way to switch back to the ladder
governor is to enable the sysfs governor switch in the kernel command line.

Because it seems nobody complained about this, the menu governor is used by
default most of the time on the system, having both governors is not really
necessary on a tickless system but there isn't a config option to disable one
or another governor.

Create a submenu for cpuidle and add a label for each governor, so we can see
the option in the menu config and enable/disable it.

The governors will be enabled depending on the CONFIG_NO_HZ option:
 - If CONFIG_NO_HZ is set, then the menu governor is selected and the ladder
   governor is optional, defaulting to 'yes'
 - If CONFIG_NO_HZ is not set, then the ladder governor is selected and the
   menu governor is optional, defaulting to 'yes'

Signed-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent d683b96b

drivers/cpuidle/Kconfig

+7 −9
Original line number Original line Diff line number Diff line 




config CPU_IDLE

menuconfig CPU_IDLE

	bool "CPU idle PM support"

	bool "CPU idle PM support"

	default y if ACPI || PPC_PSERIES

	default y if ACPI || PPC_PSERIES

	select CPU_IDLE_GOV_LADDER if (!NO_HZ && !NO_HZ_IDLE)

	select CPU_IDLE_GOV_MENU if (NO_HZ || NO_HZ_IDLE)

	help

	help

	  CPU idle is a generic framework for supporting software-controlled

	  CPU idle is a generic framework for supporting software-controlled

	  idle processor power management.  It includes modular cross-platform

	  idle processor power management.  It includes modular cross-platform
@@ -9,9 +11,10 @@ config CPU_IDLE 




	  If you're using an ACPI-enabled platform, you should say Y here.

	  If you're using an ACPI-enabled platform, you should say Y here.





if CPU_IDLE



config CPU_IDLE_MULTIPLE_DRIVERS

config CPU_IDLE_MULTIPLE_DRIVERS

        bool "Support multiple cpuidle drivers"

        bool "Support multiple cpuidle drivers"

        depends on CPU_IDLE

        default n

        default n

        help

        help

         Allows the cpuidle framework to use different drivers for each CPU.

         Allows the cpuidle framework to use different drivers for each CPU.
@@ -19,24 +22,19 @@ config CPU_IDLE_MULTIPLE_DRIVERS 
         states. If unsure say N.

         states. If unsure say N.





config CPU_IDLE_GOV_LADDER

config CPU_IDLE_GOV_LADDER

	bool

	bool "Ladder governor (for periodic timer tick)"

	depends on CPU_IDLE

	default y

	default y





config CPU_IDLE_GOV_MENU

config CPU_IDLE_GOV_MENU

	bool

	bool "Menu governor (for tickless system)"

	depends on CPU_IDLE && NO_HZ

	default y

	default y





config ARCH_NEEDS_CPU_IDLE_COUPLED

config ARCH_NEEDS_CPU_IDLE_COUPLED

	def_bool n

	def_bool n





if CPU_IDLE



config CPU_IDLE_CALXEDA

config CPU_IDLE_CALXEDA

	bool "CPU Idle Driver for Calxeda processors"

	bool "CPU Idle Driver for Calxeda processors"

	depends on ARCH_HIGHBANK

	depends on ARCH_HIGHBANK

	help

	help

	  Select this to enable cpuidle on Calxeda processors.

	  Select this to enable cpuidle on Calxeda processors.



endif
 
endif