[patch 07/22] hwmon: Fix missing it87 fan div init

[Greg Kroah-Hartman <gregkh@suse.de>]

From: Jean Delvare <khali@linux-fr.org>

Fix a bug where setting the low fan speed limits will not work if no
data was ever read through the sysfs interface and the fan clock
dividers have not been explicitely set yet either. The reason is that
data->fan_div[nr] may currently be used before it is initialized from
the chip register values. The fix is to explicitely initialize
data->fan_div[nr] before using it.

Bug reported, and fix tested, by Nicolas Mailhot.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 drivers/hwmon/it87.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- usb-2.6.orig/drivers/hwmon/it87.c
+++ usb-2.6/drivers/hwmon/it87.c
@@ -522,8 +522,15 @@ static ssize_t set_fan_min(struct device
 	struct i2c_client *client = to_i2c_client(dev);
 	struct it87_data *data = i2c_get_clientdata(client);
 	int val = simple_strtol(buf, NULL, 10);
+	u8 reg = it87_read_value(client, IT87_REG_FAN_DIV);
 
 	down(&data->update_lock);
+	switch (nr) {
+	case 0: data->fan_div[nr] = reg & 0x07; break;
+	case 1: data->fan_div[nr] = (reg >> 3) & 0x07; break;
+	case 2: data->fan_div[nr] = (reg & 0x40) ? 3 : 1; break;
+	}
+
 	data->fan_min[nr] = FAN_TO_REG(val, DIV_FROM_REG(data->fan_div[nr]));
 	it87_write_value(client, IT87_REG_FAN_MIN(nr), data->fan_min[nr]);
 	up(&data->update_lock);

--
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/