Store a device's desired enumeration power state in struct
acpi_device_power_flags during acpi_device object's initialisation.
Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
---
drivers/acpi/scan.c | 6 ++++++
include/acpi/acpi_bus.h | 3 ++-
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 1d7a02ee45e05..b077c645c9845 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -987,6 +987,8 @@ static void acpi_bus_init_power_state(struct acpi_device *device, int state)
static void acpi_bus_get_power_flags(struct acpi_device *device)
{
+ unsigned long long pre;
+ acpi_status status;
u32 i;
/* Presence of _PS0|_PR0 indicates 'power manageable' */
@@ -1008,6 +1010,10 @@ static void acpi_bus_get_power_flags(struct acpi_device *device)
if (acpi_has_method(device->handle, "_DSW"))
device->power.flags.dsw_present = 1;
+ status = acpi_evaluate_integer(device->handle, "_PRE", NULL, &pre);
+ if (ACPI_SUCCESS(status) && !pre)
+ device->power.flags.allow_low_power_probe = 1;
+
/*
* Enumerate supported power management states
*/
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 02a716a0af5d4..020b850120883 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -258,7 +258,8 @@ struct acpi_device_power_flags {
u32 power_removed:1; /* Optimize Dx->D0 */
u32 ignore_parent:1; /* Power is independent of parent power state */
u32 dsw_present:1; /* _DSW present? */
- u32 reserved:26;
+ u32 allow_low_power_probe:1; /* Allow low power state in device probe */
+ u32 reserved:25;
};
struct acpi_device_power_state {
--
2.20.1
