ACPI / scan: Treat power resources in a special way

Commit 805d410 (ACPI: Separate adding ACPI device objects from
probing ACPI drivers) introduced an ACPI power resources management
regression, because it didn't ensure that the power resources
driver bind to the struct acpi_device objects corresponding
to power resources as soon as they were created.  As a result,
ACPI power management routines may attempt to access power resource
objects before they are ready to use.

To fix this problem, tell the acpi_add_single_object() in
acpi_bus_check_add() to probe the driver for objects of type
ACPI_BUS_TYPE_POWER.  This fix has been verified to work on
HP nx6325 where the problem was first observed.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index f8a0d0f7d197..e380345b643a 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1558,7 +1558,8 @@ static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl_not_used,
                 return AE_CTRL_DEPTH;
         }
 
-        acpi_add_single_object(&device, handle, type, sta, false);
+        acpi_add_single_object(&device, handle, type, sta,
+                               type == ACPI_BUS_TYPE_POWER);
         if (!device)
                 return AE_CTRL_DEPTH;