[PATCH] opp: convert dev_warn() to dev_dbg() for duplicate OPPs

[Rafael J. Wysocki]

On Tuesday, November 18, 2014 08:38:14 AM Viresh Kumar wrote:
> On 18 November 2014 05:09, Rafael J. Wysocki <rjw at rjwysocki.net> wrote:
> > On Monday, November 17, 2014 01:38:00 PM Viresh Kumar wrote:
> >> diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
> >> index 89ced95..490e9db 100644
> >> --- a/drivers/base/power/opp.c
> >> +++ b/drivers/base/power/opp.c
> >> @@ -466,9 +466,9 @@ int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
> >>               int ret = opp->available && new_opp->u_volt == opp->u_volt ?
> >>                       0 : -EEXIST;
> >>
> >> -             dev_warn(dev, "%s: duplicate OPPs detected. Existing: freq: %lu, volt: %lu, enabled: %d. New: freq: %lu, volt: %lu, enabled: %d\n",
> >> -                      __func__, opp->rate, opp->u_volt, opp->available,
> >> -                      new_opp->rate, new_opp->u_volt, new_opp->available);
> >> +             dev_dbg(dev, "%s: duplicate OPPs detected. Existing: freq: %lu, volt: %lu, enabled: %d. New: freq: %lu, volt: %lu, enabled: %d\n",
> >> +                     __func__, opp->rate, opp->u_volt, opp->available,
> >> +                     new_opp->rate, new_opp->u_volt, new_opp->available);
> >>               mutex_unlock(&dev_opp_list_lock);
> >>               kfree(new_opp);
> >>               return ret;
> >
> > Don't you think that this may hide real bugs?
> 
> What kind of bugs exactly?
> 
> We are allowing addition of duplicate OPPs as a standard thing right now
> as cpufreq drivers don't get rid of the OPPs they create with DT. So, that
> shouldn't complain, isn't it ?

Is cpufreq the only user of OPP?  I thought there were other users, so what
about them?

> For example, what Stefan was doing was absolutely normal procedure
> and that complained for him..
> 
> The only thing we don't allow is when the existing OPP isn't available
> and we are trying to add a duplicate one. In that case we do return
> -EEXIST and so we will get errors from the upper layer.
> 
> Or do we want to destroy OPPs created with help of DT while the
> driver unloads ?

I'm not sure about that.  If they aren't useful for anything after
that, what's the benefit of keeping them around?

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.