--- addon-dell-backlight.cpp.orig	2008-03-01 23:56:50.148970029 +0100
+++ addon-dell-backlight.cpp	2008-03-01 23:57:04.877632038 +0100
@@ -184,10 +184,34 @@
         }
 
 	/* Mechanism to ensure that we always set the AC brightness when we are on AC-power etc. */
-	AC = libhal_device_get_property_bool (halctx, 
+	if (libhal_device_exists (halctx, "/org/freedesktop/Hal/devices/acpi_AC", NULL))
+	{
+		AC = libhal_device_get_property_bool (halctx, 
 					     "/org/freedesktop/Hal/devices/acpi_AC",
 					     "ac_adapter.present",
 					     &err);
+	}
+	else if (libhal_device_exists (halctx, "/org/freedesktop/Hal/devices/computer_power_supply", NULL))
+	{
+		/* Found on Dell Inspiron 1501 */
+		AC = libhal_device_get_property_bool (halctx, 
+							 "/org/freedesktop/Hal/devices/computer_power_supply",
+							 "ac_adapter.present",
+							 &err);
+	}
+	else
+	{
+		/* If we don't know, always use battery (arbitrary choice) */
+		HAL_DEBUG (("Cannot determine AC status, ac_adapter.present not found"));
+		AC = FALSE;
+	}
+	
+	/* Free err if set before re-using */
+	if (dbus_error_is_set (&err)) {
+		HAL_DEBUG (("Error determining AC status: %s", err.message));
+		dbus_error_free (&err);
+		AC = FALSE;
+	}
 
 	if (dbus_message_is_method_call (message, 
 					 "org.freedesktop.Hal.Device.LaptopPanel",