[PATCH] Linux: Only one warning if no valid voltage found

[Timothée Ravier]

Avoid filling the logs with repeated warning saying that no correct
voltage value was found for a power device. Improves the situation with
bugs https://bugzilla.redhat.com/show_bug.cgi?id=847874 and
https://bugzilla.redhat.com/show_bug.cgi?id=863524

Signed-off-by: Timothée Ravier <tim at siosm.fr>
---
 src/linux/up-device-supply.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/linux/up-device-supply.c b/src/linux/up-device-supply.c
index a93d16a..4a015d0 100644
--- a/src/linux/up-device-supply.c
+++ b/src/linux/up-device-supply.c
@@ -376,6 +376,7 @@ up_device_supply_get_design_voltage (const gchar *native_path)
 {
 	gdouble voltage;
 	gchar *device_type = NULL;
+	static GHashTable *devices_already_warned = NULL;
 
 	/* design maximum */
 	voltage = sysfs_get_double (native_path, "voltage_max_design") / 1000000.0;
@@ -413,8 +414,17 @@ up_device_supply_get_design_voltage (const gchar *native_path)
 		goto out;
 	}
 
+	/* no valid value found; display a warning the first time for each
+	 * device */
+	if (devices_already_warned == NULL) {
+		devices_already_warned = g_hash_table_new(g_str_hash, g_str_equal);
+	}
+	if (g_hash_table_lookup(devices_already_warned, native_path) == NULL) {
+		g_hash_table_insert(devices_already_warned, (gpointer) native_path, (gpointer) 1);
+		g_warning ("no valid voltage value found for device: %s", native_path);
+		g_warning ("using 10V as approximation for device: %s", native_path);
+	}
 	/* completely guess, to avoid getting zero values */
-	g_warning ("no voltage values for device %s, using 10V as approximation", native_path);
 	voltage = 10.0f;
 out:
 	g_free (device_type);
-- 
1.8.4