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| author | Patrick Titiano <ptitiano@baylibre.com> | 2014-02-28 14:10:04 +0100 |
|---|---|---|
| committer | Zhang Rui <rui.zhang@intel.com> | 2014-04-08 09:01:39 +0800 |
| commit | 9477165ec525d47abb1cb6523698e0cd89d65ddb (patch) | |
| tree | 76fd2a4df3ffdc668c9f8f3b13cc0c06815bea65 /drivers/thermal | |
| parent | 206c0cba095acbb91d552d220207d690c9b29594 (diff) | |
| download | linux-9477165ec525d47abb1cb6523698e0cd89d65ddb.tar.gz linux-9477165ec525d47abb1cb6523698e0cd89d65ddb.tar.bz2 linux-9477165ec525d47abb1cb6523698e0cd89d65ddb.zip | |
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.c | 7 |
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) |