Messages in this thread | | | Date | Fri, 03 Oct 2014 12:40:54 +0200 | From | Lukasz Majewski <> | Subject | Re: [PATCH 3/3] thermal: core: fix: Check return code of the ->get_max_state() callback |
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Hi Eduardo, Rui,
> On Wed, Sep 24, 2014 at 10:27:12AM +0200, Lukasz Majewski wrote: > > Without this check it was possible to execute cooling device > > binding code even when wrong max cooling state was read. > > > > Signed-off-by: Lukasz Majewski <l.majewski@samsung.com> > > Acked-by: Eduardo Valentin <edubezval@gmail.com> > > Rui, are you taking these patches? Do you prefer me to collect them?
I'd like to ask you NOT to apply those patches.
In short: It will cause regression on all non Exynos boards.
Explanation:
Up till now the cpu_cooling device was bind even when the get_max_state() returned -EINVAL and everything worked after late cpufreq policy initialization.
However, during this time window the thermal driver is not properly configured.
Applying PATCH2/3 and PATCH3/3 would cause bind error without any further occasion for re-bind. As a result THERAL will not be present on the target system.
It works on the Exynos boards, since at the report_trigger() function, when first trip point is reached, it is checked if cpu_cooling device is bind. If it is not (due to "fixes" at PATCH2/3 and PATCH3/3) it is rebind then.
Due to above, I think that it would be best to leave things as they are now and prepare proper fix as suggested by Eduardo.
> > Cheers > > Eduardo > > > --- > > drivers/thermal/thermal_core.c | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/thermal/thermal_core.c > > b/drivers/thermal/thermal_core.c index 747618a..8a4dc35 100644 > > --- a/drivers/thermal/thermal_core.c > > +++ b/drivers/thermal/thermal_core.c > > @@ -928,7 +928,7 @@ int thermal_zone_bind_cooling_device(struct > > thermal_zone_device *tz, struct thermal_zone_device *pos1; > > struct thermal_cooling_device *pos2; > > unsigned long max_state = 0; > > - int result; > > + int result, ret; > > > > if (trip >= tz->trips || (trip < 0 && trip != > > THERMAL_TRIPS_NONE)) return -EINVAL; > > @@ -945,7 +945,9 @@ int thermal_zone_bind_cooling_device(struct > > thermal_zone_device *tz, if (tz != pos1 || cdev != pos2) > > return -EINVAL; > > > > - cdev->ops->get_max_state(cdev, &max_state); > > + ret = cdev->ops->get_max_state(cdev, &max_state); > > + if (ret) > > + return ret; > > > > /* lower default 0, upper default max_state */ > > lower = lower == THERMAL_NO_LIMIT ? 0 : lower; > > -- > > 2.0.0.rc2 > >
-- Best regards,
Lukasz Majewski
Samsung R&D Institute Poland (SRPOL) | Linux Platform Group
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