Re: [PATCH 4/4] thermal: bang-bang governor: act on lower trip boundary

Eduardo Valentin
2016-04-27T21:54:26Z

On Mon, Apr 25, 2016 at 11:02:47AM +0800, Caesar Wang wrote:
> From: Sascha Hauer <s.hauer@pengutronix.de>
>
> With interrupt driven thermal zones we pass the lower and upper
> temperature on which shall be acted, so in the governor we have to act on
> the exact lower temperature to be consistent. Otherwise an interrupt maybe
> generated on the exact lower temperature, but the bang bang governor does
> not react.

What is the expected impact on polling driven zones that use bang bang
after this change?

>
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> Signed-off-by: Caesar Wang <wxt@rock-chips.com>
> Cc: Zhang Rui <rui.zhang@intel.com>
> Cc: Eduardo Valentin <edubezval@gmail.com>
> Cc: linux-pm@vger.kernel.org
>
> ---
>
> drivers/thermal/gov_bang_bang.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/thermal/gov_bang_bang.c b/drivers/thermal/gov_bang_bang.c
> index 70836c5..9d1dfea 100644
> --- a/drivers/thermal/gov_bang_bang.c
> +++ b/drivers/thermal/gov_bang_bang.c
> @@ -59,7 +59,7 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
> if (instance->target == 0 && tz->temperature >= trip_temp)
> instance->target = 1;
> else if (instance->target == 1 &&
> - tz->temperature < trip_temp - trip_hyst)
> + tz->temperature <= trip_temp - trip_hyst)
> instance->target = 0;
>
> dev_dbg(&instance->cdev->device, "target=%d\n",
> --
> 1.9.1
>