[gnome-power-manager] Adjust dim timeout when necessary

[Richard Hughes <rhughes src gnome org>]

commit ee2a18cb1ee2338edb5a038cd948d203d49271b4
Author: Tim Liim <tim liim alcatel-lucent com>
Date:   Wed Aug 4 09:46:20 2010 +0100

    Adjust dim timeout when necessary
    
    On slow machines, or machines that have lots to load duing login,
    the current idle time could be bigger than the requested timeout.
    In this case the scheduled idle timeout will never fire, unless
    some user activity (keyboard, mouse) resets the current idle time.
    Instead of relying on user activity to correct this issue, we need
    to adjust timeout, as related to current idle time, so the idle
    timeout will fire as designed.
    
    Signed-off-by: Richard Hughes <richard hughsie com>

 src/gpm-idle.c |   38 ++++++++++++++++++++++++++++++++++++++
 1 files changed, 38 insertions(+), 0 deletions(-)
---
diff --git a/src/gpm-idle.c b/src/gpm-idle.c
index ce6f595..555c611 100644
--- a/src/gpm-idle.c
+++ b/src/gpm-idle.c
@@ -258,14 +258,52 @@ out:
 }
 
 /**
+ *  gpm_idle_adjust_timeout_dim:
+ *  @idle_time: The new timeout we want to set, in seconds.
+ *  @timeout: Current idle time, in seconds.
+ *
+ *  On slow machines, or machines that have lots to load duing login,
+ *  the current idle time could be bigger than the requested timeout.
+ *  In this case the scheduled idle timeout will never fire, unless
+ *  some user activity (keyboard, mouse) resets the current idle time.
+ *  Instead of relying on user activity to correct this issue, we need
+ *  to adjust timeout, as related to current idle time, so the idle
+ *  timeout will fire as designed.
+ *
+ *  Return value: timeout to set, adjusted acccording to current idle time.
+ **/
+static guint
+gpm_idle_adjust_timeout_dim (guint idle_time, guint timeout)
+{
+	/* allow 2 sec margin for messaging delay. */
+	idle_time += 2;
+
+	/* Double timeout until it's larger than current idle time.
+	 * Give up for ultra slow machines. (86400 sec = 24 hours) */
+	while (timeout < idle_time && timeout < 86400 && timeout > 0) {
+		timeout *= 2;
+	}
+	return timeout;
+}
+
+/**
  * gpm_idle_set_timeout_dim:
  * @timeout: The new timeout we want to set, in seconds
  **/
 gboolean
 gpm_idle_set_timeout_dim (GpmIdle *idle, guint timeout)
 {
+	gint64 idle_time_in_msec;
+	guint timeout_adjusted;
+
 	g_return_val_if_fail (GPM_IS_IDLE (idle), FALSE);
 
+	idle_time_in_msec = gpm_idletime_get_time (idle->priv->idletime);
+	timeout_adjusted  = gpm_idle_adjust_timeout_dim (idle_time_in_msec / 1000, timeout);
+	egg_debug ("Current idle time=%lldms, timeout was %us, becomes %us after adjustment",
+		   idle_time_in_msec, timeout, timeout_adjusted);
+	timeout = timeout_adjusted;
+
 	egg_debug ("Setting dim idle timeout: %ds", timeout);
 	if (idle->priv->timeout_dim != timeout) {
 		idle->priv->timeout_dim = timeout;