Commit 5c7dd710 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Linus Torvalds

ACPI / PCI / PM: Fix device PM regression related to D3hot/D3cold

Commit 1cc0c998 ("ACPI: Fix D3hot v D3cold confusion") introduced a
bug in __acpi_bus_set_power() and changed the behavior of
acpi_pci_set_power_state() in such a way that it generally doesn't work
as expected if PCI_D3hot is passed to it as the second argument.

First off, if ACPI_STATE_D3 (equal to ACPI_STATE_D3_COLD) is passed to
__acpi_bus_set_power() and the explicit_set flag is set for the D3cold
state, the function will try to execute AML method called "_PS4", which
doesn't exist.

Fix this by adding a check to ensure that the name of the AML method
to execute for transitions to ACPI_STATE_D3_COLD is correct in
__acpi_bus_set_power().  Also make sure that the explicit_set flag
for ACPI_STATE_D3_COLD will be set if _PS3 is present and modify
acpi_power_transition() to avoid accessing power resources for
ACPI_STATE_D3_COLD, because they don't exist.

Second, if PCI_D3hot is passed to acpi_pci_set_power_state() as the
target state, the function will request a transition to
ACPI_STATE_D3_HOT instead of ACPI_STATE_D3.  However,
ACPI_STATE_D3_HOT is now only marked as supported if the _PR3 AML
method is defined for the given device, which is rare.  This causes
problems to happen on systems where devices were successfully put
into ACPI D3 by pci_set_power_state(PCI_D3hot) which doesn't work
now.  In particular, some unused graphics adapters are not turned
off as a result.

To fix this issue restore the old behavior of
acpi_pci_set_power_state(), which is to request a transition to
ACPI_STATE_D3 (equal to ACPI_STATE_D3_COLD) if either PCI_D3hot or
PCI_D3cold is passed to it as the argument.

This approach is not ideal, because generally power should not
be removed from devices if PCI_D3hot is the target power state,
but since this behavior is relied on, we have no choice but to
restore it at the moment and spend more time on designing a
better solution in the future.

References: default avatarrocko <>
Reported-by: default avatarCristian Rodríguez <>
Reported-and-tested-by: default avatarPeter <>
Signed-off-by: default avatarRafael J. Wysocki <>
Signed-off-by: default avatarLinus Torvalds <>
parent eea03647
......@@ -250,6 +250,10 @@ static int __acpi_bus_set_power(struct acpi_device *device, int state)
return -ENODEV;
/* For D3cold we should execute _PS3, not _PS4. */
if (state == ACPI_STATE_D3_COLD)
object_name[3] = '3';
* Transition Power
* ----------------
......@@ -660,7 +660,7 @@ int acpi_power_on_resources(struct acpi_device *device, int state)
int acpi_power_transition(struct acpi_device *device, int state)
int result;
int result = 0;
if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
return -EINVAL;
......@@ -679,8 +679,11 @@ int acpi_power_transition(struct acpi_device *device, int state)
* (e.g. so the device doesn't lose power while transitioning). Then,
* we dereference all power resources used in the current list.
result = acpi_power_on_list(&device->power.states[state].resources);
if (!result)
if (state < ACPI_STATE_D3_COLD)
result = acpi_power_on_list(
if (!result && device->power.state < ACPI_STATE_D3_COLD)
......@@ -908,6 +908,10 @@ static int acpi_bus_get_power_flags(struct acpi_device *device)
device->power.states[ACPI_STATE_D3].flags.valid = 1;
device->power.states[ACPI_STATE_D3].power = 0;
/* Set D3cold's explicit_set flag if _PS3 exists. */
if (device->power.states[ACPI_STATE_D3_HOT].flags.explicit_set)
device->power.states[ACPI_STATE_D3_COLD].flags.explicit_set = 1;
return 0;
......@@ -223,7 +223,7 @@ static int acpi_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
[PCI_D3hot] = ACPI_STATE_D3,
[PCI_D3cold] = ACPI_STATE_D3
int error = -EINVAL;
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