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 <khali@xxxxxxxxxxxx>
---
Documentation/hwmon/it87 | 4 ++++
drivers/hwmon/it87.c | 32 ++++++++++++++++++++++++++++++++
2 files changed, 36 insertions(+)
--- linux-2.6.33-rc8.orig/Documentation/hwmon/it87 2010-02-22 08:38:21.000000000 +0100
+++ linux-2.6.33-rc8/Documentation/hwmon/it87 2010-02-22 11:33:48.000000000 +0100
@@ -177,3 +177,7 @@ between trip point N and trip point N+1
the one of trip point N. The automatic control mode is less flexible
than the manual control mode, but it reacts faster, is more robust and
doesn't use CPU cycles.
+
+Trip points must be set properly before switching to automatic fan speed
+control mode. The driver will perform basic integrity checks before
+actually switching to automatic control mode.
--- linux-2.6.33-rc8.orig/drivers/hwmon/it87.c 2010-02-22 11:09:33.000000000 +0100
+++ linux-2.6.33-rc8/drivers/hwmon/it87.c 2010-02-23 21:31:57.000000000 +0100
@@ -719,6 +719,32 @@ static ssize_t set_fan_div(struct device
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 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) {
--
Jean Delvare
_______________________________________________
lm-sensors mailing list
lm-sensors@xxxxxxxxxxxxxx
http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
