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authorZhang Rui <rui.zhang@intel.com>2009-12-17 16:02:08 +0800
committerLen Brown <len.brown@intel.com>2009-12-28 21:47:29 -0500
commit0c99c5288eb9b1bbc9684b0ec0fd7efc578749b3 (patch)
tree67261962e0ed40fe0d4d84d703d820edd53c254f /drivers/acpi/bus.c
parent6b7b284958d47b77d06745b36bc7f36dab769d9b (diff)
ACPI: Disable explicit power state retrieval on fans
If the ACPI power state can be got both directly and indirectly, we prefer to get it indirectly. https://bugzilla.redhat.com/show_bug.cgi?id=531916 describes a system with a _PSC method for the fan that always returns "on". There's no benefit in us always requesting the state of the fan when performing transitions - we want to do everything we can to ensure that the fan turns on when it should do, not risk hardware damage by believing the hardware when it tells us the fan is already on. Given that the Leading Other OS(tm) works fine on this machine, it seems likely that it behaves in much this way. inspired-by: Matthew Garrett <mjg@redhat.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/acpi/bus.c')
-rw-r--r--drivers/acpi/bus.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index cf761b904e4..ae9226de93a 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -190,16 +190,16 @@ int acpi_bus_get_power(acpi_handle handle, int *state)
* Get the device's power state either directly (via _PSC) or
* indirectly (via power resources).
*/
- if (device->power.flags.explicit_get) {
+ if (device->power.flags.power_resources) {
+ result = acpi_power_get_inferred_state(device);
+ if (result)
+ return result;
+ } else if (device->power.flags.explicit_get) {
status = acpi_evaluate_integer(device->handle, "_PSC",
NULL, &psc);
if (ACPI_FAILURE(status))
return -ENODEV;
device->power.state = (int)psc;
- } else if (device->power.flags.power_resources) {
- result = acpi_power_get_inferred_state(device);
- if (result)
- return result;
}
*state = device->power.state;