From cccfc9c4bb3c7888f8249b36e08d6e115238c613 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Fri, 5 Mar 2010 22:17:21 +0100 Subject: hwmon: (it87) Validate auto pwm settings Before switching to automatic fan control mode, make sure that all the trip points make sense. Otherwise, the control loop could lead to weird fan behavior. Signed-off-by: Jean Delvare --- drivers/hwmon/it87.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) (limited to 'drivers/hwmon') diff --git a/drivers/hwmon/it87.c b/drivers/hwmon/it87.c index bbb0c7443b9..1002befd87d 100644 --- a/drivers/hwmon/it87.c +++ b/drivers/hwmon/it87.c @@ -719,6 +719,32 @@ static ssize_t set_fan_div(struct device *dev, struct device_attribute *attr, mutex_unlock(&data->update_lock); return count; } + +/* Returns 0 if OK, -EINVAL otherwise */ +static int check_trip_points(struct device *dev, int nr) +{ + const struct it87_data *data = dev_get_drvdata(dev); + int i, err = 0; + + if (has_old_autopwm(data)) { + for (i = 0; i < 3; i++) { + if (data->auto_temp[nr][i] > data->auto_temp[nr][i + 1]) + err = -EINVAL; + } + for (i = 0; i < 2; i++) { + if (data->auto_pwm[nr][i] > data->auto_pwm[nr][i + 1]) + err = -EINVAL; + } + } + + if (err) { + dev_err(dev, "Inconsistent trip points, not switching to " + "automatic mode\n"); + dev_err(dev, "Adjust the trip points and try again\n"); + } + return err; +} + static ssize_t set_pwm_enable(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { @@ -731,6 +757,12 @@ static ssize_t set_pwm_enable(struct device *dev, if (strict_strtol(buf, 10, &val) < 0 || val < 0 || val > 2) return -EINVAL; + /* Check trip points before switching to automatic mode */ + if (val == 2) { + if (check_trip_points(dev, nr) < 0) + return -EINVAL; + } + mutex_lock(&data->update_lock); if (val == 0) { -- cgit v1.2.3-70-g09d2