Patch "hwmon: (gpio-fan) Remove un-necessary speed_index lookup for thermal hook" has been added to the 4.4-stable tree

Patch "hwmon: (gpio-fan) Remove un-necessary speed_index lookup for thermal hook" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    hwmon: (gpio-fan) Remove un-necessary speed_index lookup for thermal hook

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     hwmon-gpio-fan-remove-un-necessary-speed_index-lookup-for-thermal-hook.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 000e0949148382c4962489593a2f05504c2a6771 Mon Sep 17 00:00:00 2001
From: Nishanth Menon <nm@ti.com>
Date: Fri, 19 Feb 2016 18:09:51 -0600
Subject: hwmon: (gpio-fan) Remove un-necessary speed_index lookup for thermal hook

From: Nishanth Menon <nm@ti.com>

commit 000e0949148382c4962489593a2f05504c2a6771 upstream.

Thermal hook gpio_fan_get_cur_state is only interested in knowing
the current speed index that was setup in the system, this is
already available as part of fan_data->speed_index which is always
set by set_fan_speed. Using get_fan_speed_index is useful when we
have no idea about the fan speed configuration (for example during
fan_ctrl_init).

When thermal framework invokes
gpio_fan_get_cur_state=>get_fan_speed_index via gpio_fan_get_cur_state
especially in a polled configuration for thermal governor, we
basically hog the i2c interface to the extent that other functions
fail to get any traffic out :(.

Instead, just provide the last state set in the driver - since the gpio
fan driver is responsible for the fan state immaterial of override, the
fan_data->speed_index should accurately reflect the state.

Fixes: b5cf88e46bad ("(gpio-fan): Add thermal control hooks")
Reported-by: Tony Lindgren <tony@atomide.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/hwmon/gpio-fan.c |    7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

--- a/drivers/hwmon/gpio-fan.c
+++ b/drivers/hwmon/gpio-fan.c
@@ -406,16 +406,11 @@ static int gpio_fan_get_cur_state(struct
 				  unsigned long *state)
 {
 	struct gpio_fan_data *fan_data = cdev->devdata;
-	int r;
 
 	if (!fan_data)
 		return -EINVAL;
 
-	r = get_fan_speed_index(fan_data);
-	if (r < 0)
-		return r;
-
-	*state = r;
+	*state = fan_data->speed_index;
 	return 0;
 }
 


Patches currently in stable-queue which might be from nm@ti.com are

queue-4.4/hwmon-gpio-fan-remove-un-necessary-speed_index-lookup-for-thermal-hook.patch