linux: Add NoPollBatteries configuration option

For system integrators. If your firmware is helpful to user space
and automatically sends out uevent when the battery level changes
(rather than just the battery state) as on most machines,
you can enable "NoPollBatteries" in the configuration option,
and reduce power consumption from UPower and its listeners.

2 files changed, 22 insertions, 3 deletions

diff --git a/etc/UPower.conf b/etc/UPower.conf
index 801f52f..920b256 100644
--- a/etc/UPower.conf
+++ b/etc/UPower.conf
@@ -26,6 +26,15 @@ EnableWattsUpPro=false
 # default=false
 PollDockDevices=false
 
+# Don't poll the kernel for battery level changes.
+#
+# Some hardware will send us battery level changes through
+# events, rather than us having to poll for it. This option
+# allows disabling polling for hardware that sends out events.
+#
+# default=false
+NoPollBatteries=false
+
 # Do we ignore the lid state
 #
 # Some laptops are broken. The lid state is either inverted, or stuck
diff --git a/src/linux/up-device-supply.c b/src/linux/up-device-supply.c
index 5fb7cb0..3a3ceea 100644
--- a/src/linux/up-device-supply.c
+++ b/src/linux/up-device-supply.c
@@ -34,6 +34,7 @@
 #include <gudev/gudev.h>
 
 #include "sysfs-utils.h"
+#include "up-config.h"
 #include "up-types.h"
 #include "up-device-supply.h"
 
@@ -58,7 +59,8 @@ struct UpDeviceSupplyPrivate
 	guint			 energy_old_first;
 	gdouble			 rate_old;
 	guint			 unknown_retries;
-	gboolean		 enable_poll;
+	gboolean		 enable_poll; /* calculated */
+	gboolean		 disable_battery_poll; /* from configuration */
 	gboolean		 is_power_supply;
 	gboolean		 shown_invalid_voltage_warning;
 };
@@ -1110,8 +1112,10 @@ up_device_supply_refresh (UpDevice *device)
 		up_device_supply_disable_poll (device);
 		ret = up_device_supply_refresh_battery (supply, &state);
 		/* Seems that we don't get change uevents from the
-		 * kernel on some BIOS types */
-		up_device_supply_setup_poll (device, state);
+		 * kernel on some BIOS types, but if polling
+		 * is disabled in the configuration, do nothing */
+		if (!supply->priv->disable_battery_poll)
+			up_device_supply_setup_poll (device, state);
 		break;
 	default:
 		up_device_supply_disable_poll (device);
@@ -1135,6 +1139,8 @@ up_device_supply_refresh (UpDevice *device)
 static void
 up_device_supply_init (UpDeviceSupply *supply)
 {
+	UpConfig *config;
+
 	supply->priv = UP_DEVICE_SUPPLY_GET_PRIVATE (supply);
 	supply->priv->enable_poll = TRUE;
 
@@ -1143,6 +1149,10 @@ up_device_supply_init (UpDeviceSupply *supply)
 	supply->priv->energy_old_timespec = g_new (GTimeVal, UP_DEVICE_SUPPLY_ENERGY_OLD_LENGTH);
 
 	supply->priv->shown_invalid_voltage_warning = FALSE;
+
+	config = up_config_new ();
+	supply->priv->disable_battery_poll = up_config_get_boolean (config, "NoPollBatteries");
+	g_object_unref (config);
 }
 
 /**