Hi Guenter,
On Mon, 19 Jan 2015 09:19:52 -0800, Guenter Roeck wrote:
> Subtracting an unsigned long from a signed value causes an overflow with large
> values. Use clamp_val() to reduce the number range prior to subtracting it
> from the temperature limit.
>
> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> ---
> drivers/hwmon/jc42.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/hwmon/jc42.c b/drivers/hwmon/jc42.c
> index f8e3bbb..a46cb65 100644
> --- a/drivers/hwmon/jc42.c
> +++ b/drivers/hwmon/jc42.c
> @@ -312,7 +312,9 @@ static ssize_t set_temp_crit_hyst(struct device *dev,
> if (kstrtoul(buf, 10, &val) < 0)
> return -EINVAL;
>
> + val = clamp_val(val, 0, JC42_TEMP_MAX);
> diff = jc42_temp_from_reg(data->temp[t_crit]) - val;
> +
> hyst = 0;
> if (diff > 0) {
> if (diff < 2250)
Correct, however I am wondering why we reject negative hysteresis
values in the first place? My chips have the hysteresis delta at -3°C
by default, I can set temp1_crit to -1°C and temp1_crit_hyst will read
back -4°C as expected, however the driver doesn't let me change the
hysteresis after that.
I agree that JC42_CAP_RANGE (extended temperature range) was certainly
meant for temp1_min rather than temp1_max or temp1_crit, but I still
believe the driver should not limit the user that way. I'll send a
patch, let me know what you think.
Anyway the fix above is correct, so:
Reviewed-by: Jean Delvare <jdelvare@xxxxxxx>
--
Jean Delvare
SUSE L3 Support
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