[3.13.y.z extended stable] Patch "hwmon: (gpio-fan) Prevent overflow problem when writing large limits" has been added to staging queue

Kamal Mostafa kamal at canonical.com
Mon Sep 15 22:07:56 UTC 2014

This is a note to let you know that I have just added a patch titled

    hwmon: (gpio-fan) Prevent overflow problem when writing large limits

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:


This patch is scheduled to be released in version

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see



>From b460f58dce775bcea22e861fbb34b0c48d0f30f6 Mon Sep 17 00:00:00 2001
From: Axel Lin <axel.lin at ingics.com>
Date: Sat, 2 Aug 2014 13:36:38 +0800
Subject: hwmon: (gpio-fan) Prevent overflow problem when writing large limits

commit 2565fb05d1e9fc0831f7b1c083bcfcb1cba1f020 upstream.

On platforms with sizeof(int) < sizeof(unsigned long), writing a rpm value
larger than MAXINT will result in unpredictable limit values written to the
chip. Avoid auto-conversion from unsigned long to int to fix the problem.

Signed-off-by: Axel Lin <axel.lin at ingics.com>
Signed-off-by: Guenter Roeck <linux at roeck-us.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
 drivers/hwmon/gpio-fan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/gpio-fan.c b/drivers/hwmon/gpio-fan.c
index 73181be..814f7ee 100644
--- a/drivers/hwmon/gpio-fan.c
+++ b/drivers/hwmon/gpio-fan.c
@@ -173,7 +173,7 @@ static int get_fan_speed_index(struct gpio_fan_data *fan_data)
 	return -ENODEV;

-static int rpm_to_speed_index(struct gpio_fan_data *fan_data, int rpm)
+static int rpm_to_speed_index(struct gpio_fan_data *fan_data, unsigned long rpm)
 	struct gpio_fan_speed *speed = fan_data->speed;
 	int i;

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