On 02/19/2016 04:09 PM, Nishanth Menon wrote:
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 <[email protected]> Cc: Guenter Roeck <[email protected]> Cc: Eduardo Valentin <[email protected]> Signed-off-by: Nishanth Menon <[email protected]> ---
Applied. Thanks, Guenter
Test logs from linus master v4.5-rc4-137-g23300f657594 Without fix: http://paste.ubuntu.org.cn/3948618 With Fix: http://paste.ubuntu.org.cn/3948617 drivers/hwmon/gpio-fan.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/drivers/hwmon/gpio-fan.c b/drivers/hwmon/gpio-fan.c index 82de3deeb18a..685568b1236d 100644 --- a/drivers/hwmon/gpio-fan.c +++ b/drivers/hwmon/gpio-fan.c @@ -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; }
