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

Commit 1cc0c998fdf2 ("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: https://bugzilla.kernel.org/show_bug.cgi?id=43228
Reported-by: rocko <rockorequin@hotmail.com>
Reported-by: Cristian Rodríguez <crrodriguez@opensuse.org>
Reported-and-tested-by: Peter <lekensteyn@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 3263b68..3188da3 100644 (file)
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -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
         * ----------------

diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c
index 330bb4d..0500f71 100644 (file)
--- a/drivers/acpi/power.c
+++ b/drivers/acpi/power.c
@@ -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(
+                       &device->power.states[state].resources);
+
+       if (!result && device->power.state < ACPI_STATE_D3_COLD)
                acpi_power_off_list(
                        &device->power.states[device->power.state].resources);
 

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 7417267..85cbfdc 100644 (file)
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -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;
+
        acpi_bus_init_power(device);
 
        return 0;

diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 1929c0c..61e2fef 100644 (file)
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -223,7 +223,7 @@ static int acpi_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
                [PCI_D0] = ACPI_STATE_D0,
                [PCI_D1] = ACPI_STATE_D1,
                [PCI_D2] = ACPI_STATE_D2,
-               [PCI_D3hot] = ACPI_STATE_D3_HOT,
+               [PCI_D3hot] = ACPI_STATE_D3,
                [PCI_D3cold] = ACPI_STATE_D3
        };
        int error = -EINVAL;