diff options
| author | Vic Yang <victoryang@google.com> | 2012-03-15 14:16:52 +0800 |
|---|---|---|
| committer | Vic Yang <victoryang@google.com> | 2012-03-16 07:25:37 +0800 |
| commit | 826e811493c5f6ead44a4a77ec39b2d3b3a9e042 (patch) | |
| tree | d2dc660c97a2342e064c8e0513063c421670b8c7 | |
| parent | 0cde4cfec35d34fb77c75d655d098390b70c8655 (diff) | |
| download | chrome-ec-826e811493c5f6ead44a4a77ec39b2d3b3a9e042.tar.gz | |
Prevent fan from keep turning on and off.
Modify thermal engine to treat temperature threshold as a 3-degree range
instead of a certain value. This way the fan do not keep turning on and
off, while the temperature floating around the threshold value.
Signed-off-by: Vic Yang <victoryang@google.com>
BUG=chrome-os-partner:8466
TEST=Set threshold to current temperature. The fan turns on and does not
immediately turns off.
Change-Id: Iad1de05a409dbbc573a8ffd0ece0dc7961b20806
| -rw-r--r-- | common/thermal.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/common/thermal.c b/common/thermal.c index 650b6ca5c3..1bdeaadaec 100644 --- a/common/thermal.c +++ b/common/thermal.c @@ -130,7 +130,15 @@ static inline void update_and_check_stat(int temp, overheated[threshold_id] = 1; } } - else + else if (ot_count[sensor_id][threshold_id] >= 10 && + temp >= threshold - 3) { + /* Once the threshold is reached, only if the temperature + * drops to 3 degrees below threshold do we deassert + * overheated signal. This is to prevent temperature + * oscillating around the threshold causing threshold + * keep being triggered. */ + overheated[threshold_id] = 1; + } else ot_count[sensor_id][threshold_id] = 0; } |