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@xxxxxxxxxxxxxxx> know about it.
>From 000e0949148382c4962489593a2f05504c2a6771 Mon Sep 17 00:00:00 2001
From: Nishanth Menon <nm@xxxxxx>
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@xxxxxx>
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@xxxxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Cc: Eduardo Valentin <edubezval@xxxxxxxxx>
Signed-off-by: Nishanth Menon <nm@xxxxxx>
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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@xxxxxx are
queue-4.4/hwmon-gpio-fan-remove-un-necessary-speed_index-lookup-for-thermal-hook.patch
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