X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=drivers%2Facpi%2Fdevice_pm.c;h=31c217a42839dce40ee2039cd38f36d935bda543;hb=5dbc746960b5cd62c558cd6663697afd41f59d39;hp=bc493aa3af19d87e42a18da312815de3c6fbb125;hpb=42d887a68013b0a04f7b8ebfa4999a8d5df6775c;p=firefly-linux-kernel-4.4.55.git

diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index bc493aa3af19..31c217a42839 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -278,16 +278,38 @@ int acpi_bus_init_power(struct acpi_device *device)
 		if (result)
 			return result;
 	} else if (state == ACPI_STATE_UNKNOWN) {
-		/* No power resources and missing _PSC? Try to force D0. */
+		/*
+		 * No power resources and missing _PSC?  Cross fingers and make
+		 * it D0 in hope that this is what the BIOS put the device into.
+		 * [We tried to force D0 here by executing _PS0, but that broke
+		 * Toshiba P870-303 in a nasty way.]
+		 */
 		state = ACPI_STATE_D0;
-		result = acpi_dev_pm_explicit_set(device, state);
-		if (result)
-			return result;
 	}
 	device->power.state = state;
 	return 0;
 }
 
+/**
+ * acpi_device_fix_up_power - Force device with missing _PSC into D0.
+ * @device: Device object whose power state is to be fixed up.
+ *
+ * Devices without power resources and _PSC, but having _PS0 and _PS3 defined,
+ * are assumed to be put into D0 by the BIOS.  However, in some cases that may
+ * not be the case and this function should be used then.
+ */
+int acpi_device_fix_up_power(struct acpi_device *device)
+{
+	int ret = 0;
+
+	if (!device->power.flags.power_resources
+	    && !device->power.flags.explicit_get
+	    && device->power.state == ACPI_STATE_D0)
+		ret = acpi_dev_pm_explicit_set(device, ACPI_STATE_D0);
+
+	return ret;
+}
+
 int acpi_bus_update_power(acpi_handle handle, int *state_p)
 {
 	struct acpi_device *device;