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Commit 07eab46d authored by Jean Delvare's avatar Jean Delvare Committed by Linus Torvalds
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[PATCH] hwmon: Fix missing it87 fan div init 



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: default avatarJean Delvare <khali@linux-fr.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent d0d3cd69

drivers/hwmon/it87.c

+7 −0
Original line number Diff line number Diff line
@@ -522,8 +522,15 @@ static ssize_t set_fan_min(struct device *dev, struct device_attribute *attr, 
	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);