Commit ad5a449b authored Jul 04, 2019 by Dexuan Cui Committed by Rafael J. Wysocki Jul 06, 2019

ACPI: PM: Make acpi_sleep_state_supported() non-static



With some upcoming patches to save/restore the Hyper-V drivers related
states, a Linux VM running on Hyper-V will be able to hibernate. When
a Linux VM hibernates, unluckily we must disable the memory hot-add/remove
and balloon up/down capabilities in the hv_balloon driver
(drivers/hv/hv_balloon.c), because these can not really work according to
the design of the related back-end driver on the host.

By default, Hyper-V does not enable the virtual ACPI S4 state for a VM;
on recent Hyper-V hosts, the administrator is able to enable the virtual
ACPI S4 state for a VM, so we hope to use the presence of the virtual ACPI
S4 state as a hint for hv_balloon to disable the aforementioned
capabilities. In this way, hibernation will work more reliably, from the
user's perspective.

By marking acpi_sleep_state_supported() non-static, we'll be able to
implement a hv_is_hibernation_supported() API in the always-built-in
module arch/x86/hyperv/hv_init.c, and the API will be called by hv_balloon.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

parent f850a48a

drivers/acpi/sleep.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -79,7 +79,7 @@ static int acpi_sleep_prepare(u32 acpi_state)
		return 0;
		}

		static bool acpi_sleep_state_supported(u8 sleep_state)
		bool acpi_sleep_state_supported(u8 sleep_state)
		{
		acpi_status status;
		u8 type_a, type_b;

include/acpi/acpi_bus.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -664,6 +664,12 @@ static inline int acpi_pm_set_bridge_wakeup(struct device *dev, bool enable)
		}
		#endif

		#ifdef CONFIG_ACPI_SYSTEM_POWER_STATES_SUPPORT
		bool acpi_sleep_state_supported(u8 sleep_state);
		#else
		static inline bool acpi_sleep_state_supported(u8 sleep_state) { return false; }
		#endif

		#ifdef CONFIG_ACPI_SLEEP
		u32 acpi_target_system_state(void);
		#else

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