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ACPI: scan: Turn off unused power resources during initialization

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It is reported that on certain platforms there are power resources
that are not associated with any devices physically present in the
platform.  Those power resources are expected to be turned off by
the OS in accordance with the ACPI specification (section 7.3 of
ACPI 6.4) which currently is not done by Linux and that may lead
to obscure issues.

For instance, leaving those power resources in the "on" state may
prevent the platform from reaching the lowest power state in
suspend-to-idle which leads to excessive power draw.

For this reason, turn all of the unused ACPI power resources off
at the end of the initial namespace scan for devices in analogy with
resume from suspend-to-RAM.

Link: https://uefi.org/specs/ACPI/6.4/07_Power_and_Performance_Mgmt/device-power-management-objects.html
Reported-by: David Box <david.e.box@linux.intel.com>
Tested-by: Wendy Wang <wendy.wang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Rafael J. Wysocki 2021-03-18 19:25:12 +01:00
parent 0d02ec6b31
commit 4b9ee772ea
4 changed files with 4 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

1
drivers/acpi/internal.h
View file

@ -139,6 +139,7 @@ int acpi_device_sleep_wake(struct acpi_device *dev,
int acpi_power_get_inferred_state(struct acpi_device *device, int *state);
int acpi_power_on_resources(struct acpi_device *device, int state);
int acpi_power_transition(struct acpi_device *device, int state);
void acpi_turn_off_unused_power_resources(void);
/* --------------------------------------------------------------------------
Device Power Management

2
drivers/acpi/power.c
View file

@ -996,6 +996,7 @@ void acpi_resume_power_resources(void)
mutex_unlock(&power_resource_list_lock);
}
#endif
void acpi_turn_off_unused_power_resources(void)
{
@ -1025,4 +1026,3 @@ void acpi_turn_off_unused_power_resources(void)
mutex_unlock(&power_resource_list_lock);
}
#endif

2
drivers/acpi/scan.c
View file

@ -2360,6 +2360,8 @@ int __init acpi_scan_init(void)
}
}
acpi_turn_off_unused_power_resources();
acpi_scan_initialized = true;
out:

1
drivers/acpi/sleep.h
View file

@ -8,7 +8,6 @@ extern struct list_head acpi_wakeup_device_list;
extern struct mutex acpi_device_lock;
extern void acpi_resume_power_resources(void);
extern void acpi_turn_off_unused_power_resources(void);
static inline acpi_status acpi_set_waking_vector(u32 wakeup_address)
{