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ACPI / PM: Avoid infinite recurrence while registering power resources

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There is at least one BIOS with a DSDT containing a power resource
object with a _PR0 entry pointing back to that power resource.  In
consequence, while registering that power resource
acpi_bus_get_power_flags() sees that it depends on itself and tries
to register it again, which leads to an infinitely deep recurrence.
This problem was introduced by commit bf325f9538d8c89312be305b9779e
(ACPI / PM: Register power resource devices as soon as they are
needed).

To fix this problem use the observation that power resources cannot
be power manageable and prevent acpi_bus_get_power_flags() from
being called for power resource objects.

References: https://bugzilla.kernel.org/show_bug.cgi?id=31872
Reported-and-tested-by: Pascal Dormeau <pdormeau@free.fr>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Len Brown <lenb@kernel.org>
Cc: stable@kernel.org
This commit is contained in:
Rafael J. Wysocki 2011-04-26 11:33:18 +02:00
parent 22110faf8c
commit 7bed50c5ed
1 changed files with 4 additions and 0 deletions
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4
drivers/acpi/scan.c
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@ -943,6 +943,10 @@ static int acpi_bus_get_flags(struct acpi_device *device)
if (ACPI_SUCCESS(status))
device->flags.lockable = 1;
/* Power resources cannot be power manageable. */
if (device->device_type == ACPI_BUS_TYPE_POWER)
return 0;
/* Presence of _PS0|_PR0 indicates 'power manageable' */
status = acpi_get_handle(device->handle, "_PS0", &temp);
if (ACPI_FAILURE(status))