Commit 1c2a66d4 authored by Mario Limonciello's avatar Mario Limonciello Committed by Rafael J. Wysocki
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ACPI: x86: s2idle: Add a function to get LPS0 constraint for a device 



Other parts of the kernel may use LPS0 constraints information to make
decisions on what power state to put a device into.

Signed-off-by: default avatarMario Limonciello <mario.limonciello@amd.com>
[ rjw: Rewrite kerneldoc, rearrange if () statement, edit subject and
  changelog ]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 41233988

drivers/acpi/x86/s2idle.c

+24 −0
Original line number Diff line number Diff line
@@ -299,6 +299,30 @@ static void lpi_device_get_constraints(void) 
	ACPI_FREE(out_obj);

}



/**

 * acpi_get_lps0_constraint - Get the LPS0 constraint for a device.

 * @adev: Device to get the constraint for.

 *

 * The LPS0 constraint is the shallowest (minimum) power state in which the

 * device can be so as to allow the platform as a whole to achieve additional

 * energy conservation by utilizing a system-wide low-power state.

 *

 * Returns:

 *  - ACPI power state value of the constraint for @adev on success.

 *  - Otherwise, ACPI_STATE_UNKNOWN.

 */

int acpi_get_lps0_constraint(struct acpi_device *adev)

{

	struct lpi_constraints *entry;



	for_each_lpi_constraint(entry) {

		if (adev->handle == entry->handle)

			return entry->min_dstate;

	}



	return ACPI_STATE_UNKNOWN;

}



static void lpi_check_constraints(void)

{

	struct lpi_constraints *entry;

include/linux/acpi.h

+6 −0
Original line number Diff line number Diff line
@@ -1109,6 +1109,12 @@ struct acpi_s2idle_dev_ops { 
};

int acpi_register_lps0_dev(struct acpi_s2idle_dev_ops *arg);

void acpi_unregister_lps0_dev(struct acpi_s2idle_dev_ops *arg);

int acpi_get_lps0_constraint(struct acpi_device *adev);

#else /* CONFIG_SUSPEND && CONFIG_X86 */

static inline int acpi_get_lps0_constraint(struct device *dev)

{

	return ACPI_STATE_UNKNOWN;

}

#endif /* CONFIG_SUSPEND && CONFIG_X86 */

#ifndef CONFIG_IA64

void arch_reserve_mem_area(acpi_physical_address addr, size_t size);