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

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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>
Cc: stable@vger.kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Nishanth Menon 2016-02-19 18:09:51 -06:00 committed by Guenter Roeck
parent acc1469439
commit 000e094914
1 changed files with 1 additions and 6 deletions
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7
drivers/hwmon/gpio-fan.c
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@ -406,16 +406,11 @@ static int gpio_fan_get_cur_state(struct thermal_cooling_device *cdev,
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;
}