From b3785492268f9f3cdaa9722facb84b266dcf8bf6 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 1 Feb 2013 23:43:02 +0100 Subject: ACPI / PM: Do not power manage devices in unknown initial states In general, for ACPI device power management to work, the initial power states of devices must be known (otherwise, we wouldn't be able to keep track of power resources, for example). Hence, if it is impossible to determine the initial ACPI power states of some devices, they can't be regarded as power-manageable using ACPI. For this reason, modify acpi_bus_get_power_flags() to clear the power_manageable flag if acpi_bus_init_power() fails and add some extra fallback code to acpi_bus_init_power() to cover broken BIOSes that provide _PS0/_PS3 without _PSC for some devices. Verified to work on my HP nx6325 that has this problem. Signed-off-by: Rafael J. Wysocki Tested-by: Peter Wu --- drivers/acpi/device_pm.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'drivers/acpi/device_pm.c') diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c index 3ef075b..164d609 100644 --- a/drivers/acpi/device_pm.c +++ b/drivers/acpi/device_pm.c @@ -330,6 +330,12 @@ int acpi_bus_init_power(struct acpi_device *device) result = acpi_dev_pm_explicit_set(device, state); if (result) return result; + } else if (state == ACPI_STATE_UNKNOWN) { + /* No power resources and missing _PSC? Try to force D0. */ + state = ACPI_STATE_D0; + result = acpi_dev_pm_explicit_set(device, state); + if (result) + return result; } device->power.state = state; return 0; -- cgit v1.1