Messages in this thread | | | Date | Thu, 2 Oct 2014 17:13:31 -0400 | From | Eduardo Valentin <> | Subject | Re: [PATCH 1/3] thermal: step_wise: fix: Prevent from binary overflow when trend is dropping |
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Hello Lukasz,
On Wed, Sep 24, 2014 at 10:27:10AM +0200, Lukasz Majewski wrote: > It turns out that some boards can have instance->lower greater than 0 and > when thermal trend is dropping it results with next_target equal to -1. > > Since the next_target is defined as unsigned long it is interpreted as > 0xFFFFFFFF and larger than instance->upper. > As a result the next_target is set to instance->upper which ramps up to > maximal cooling device target when the temperature is steadily decreasing. >
Thanks for finding a problem and sending a fix.
Can you please explain a little more on how next_target reaches -1 when lower is greater than 0?
> Signed-off-by: Lukasz Majewski <l.majewski@samsung.com> > --- > drivers/thermal/step_wise.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/thermal/step_wise.c b/drivers/thermal/step_wise.c > index 3b54c2c..fdd1f52 100644 > --- a/drivers/thermal/step_wise.c > +++ b/drivers/thermal/step_wise.c > @@ -77,7 +77,7 @@ static unsigned long get_target_state(struct thermal_instance *instance, > next_target = instance->upper; > break; > case THERMAL_TREND_DROPPING: > - if (cur_state == instance->lower) { > + if (cur_state <= instance->lower) { > if (!throttle) > next_target = THERMAL_NO_TARGET; > } else { > -- > 2.0.0.rc2 >
Eduardo
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