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authorPatrick Titiano <ptitiano@baylibre.com>2014-02-28 14:10:04 +0100
committerZhang Rui <rui.zhang@intel.com>2014-04-08 09:01:39 +0800
commit9477165ec525d47abb1cb6523698e0cd89d65ddb (patch)
tree76fd2a4df3ffdc668c9f8f3b13cc0c06815bea65 /drivers/thermal
parent206c0cba095acbb91d552d220207d690c9b29594 (diff)
downloadlinux-9477165ec525d47abb1cb6523698e0cd89d65ddb.tar.bz2
thermal: rcar-thermal: update thermal zone only when temperature changes
Avoid updating the thermal zone in case an IRQ was triggered but the temperature didn't effectively change. Note this is not a driver issue. Below is a captured debug trace illustrating the purpose of this patch: out of 8 thermal zone updates, only 2 are actually necessary. [ 41.120000] rcar_thermal_work(): cctemp=25000 [ 41.120000] rcar_thermal_work(): nctemp=30000 [ 41.120000] rcar_thermal_work(): temp is now 30000C, update thermal zone [ 58.990000] rcar_thermal_work(): cctemp=30000 [ 58.990000] rcar_thermal_work(): nctemp=30000 [ 58.990000] rcar_thermal_work(): same temp, do not update thermal zone [ 59.290000] rcar_thermal_work(): cctemp=30000 [ 59.290000] rcar_thermal_work(): nctemp=30000 [ 59.290000] rcar_thermal_work(): same temp, do not update thermal zone [ 59.590000] rcar_thermal_work(): cctemp=30000 [ 59.590000] rcar_thermal_work(): nctemp=30000 [ 59.590000] rcar_thermal_work(): same temp, do not update thermal zone [ 59.890000] rcar_thermal_work(): cctemp=30000 [ 59.890000] rcar_thermal_work(): nctemp=30000 [ 59.890000] rcar_thermal_work(): same temp, do not update thermal zone [ 60.190000] rcar_thermal_work(): cctemp=30000 [ 60.190000] rcar_thermal_work(): nctemp=30000 [ 60.190000] rcar_thermal_work(): same temp, do not update thermal zone [ 60.490000] rcar_thermal_work(): cctemp=30000 [ 60.490000] rcar_thermal_work(): nctemp=30000 [ 60.490000] rcar_thermal_work(): same temp, do not update thermal zone [ 60.790000] rcar_thermal_work(): cctemp=30000 [ 60.790000] rcar_thermal_work(): nctemp=35000 [ 60.790000] rcar_thermal_work(): temp is now 35000C, update thermal zone I suspect this may be due to sensor sampling accuracy / fluctuation, but no formal proof. Signed-off-by: Patrick Titiano <ptitiano@baylibre.com> Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Diffstat (limited to 'drivers/thermal')
-rw-r--r--drivers/thermal/rcar_thermal.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/thermal/rcar_thermal.c b/drivers/thermal/rcar_thermal.c
index 88cfeec6a28f..5a37940b02c9 100644
--- a/drivers/thermal/rcar_thermal.c
+++ b/drivers/thermal/rcar_thermal.c
@@ -299,12 +299,17 @@ static void _rcar_thermal_irq_ctrl(struct rcar_thermal_priv *priv, int enable)
static void rcar_thermal_work(struct work_struct *work)
{
struct rcar_thermal_priv *priv;
+ unsigned long cctemp, nctemp;
priv = container_of(work, struct rcar_thermal_priv, work.work);
+ rcar_thermal_get_temp(priv->zone, &cctemp);
rcar_thermal_update_temp(priv);
rcar_thermal_irq_enable(priv);
- thermal_zone_device_update(priv->zone);
+
+ rcar_thermal_get_temp(priv->zone, &nctemp);
+ if (nctemp != cctemp)
+ thermal_zone_device_update(priv->zone);
}
static u32 rcar_thermal_had_changed(struct rcar_thermal_priv *priv, u32 status)