Re: [PATCH 2/2] opp: quiet down WARN when no valid OPPs remain

[Viresh Kumar]

On 07-01-20, 14:57, MichaÅ MirosÅaw wrote:
> On Tue, Jan 07, 2020 at 05:00:55PM +0530, Viresh Kumar wrote:
> > On 07-01-20, 10:58, MichaÅ MirosÅaw wrote:
> > > On Tue, Jan 07, 2020 at 12:11:29PM +0530, Viresh Kumar wrote:
> > > > On 03-01-20, 20:36, MichaÅ MirosÅaw wrote:
> > > > > Per CPU screenful of backtraces is not really that useful. Replace
> > > > > WARN with a diagnostic discriminating common causes of empty OPP table.
> > > > But why should a platform have an OPP table in DT where none of them works for
> > > > it ? I added the warn intentionally here just for that case.
> > > Hmm. I guess we can make it WARN_ON_ONCE instead of removing it
> > I am not sure this will get triggered more than once normally anyway, isn't it ?
> 
> It is triggered once per core.

What platform it is ? Maybe because cpufreq driver failed to initialize the
policy for all CPUs and so this is getting repeated.

> > > , but I
> > > don't think the backtrace is ever useful in this case.
> > Hmm, I am less concerned about backtraces than highlighting problem in a serious
> > way. The simple print messages are missed many times by people and probably
> > that's why I used a WARN instead.
> 
> > 
> > > Empty table can
> > > be because eg. you run old DT on newer hardware version.
> > 
> > Hmm, but then a big warning isn't that bad as we need to highlight the issue to
> > everyone as cpufreq won't be working. isn't it ?
> 
> A user normally can't do much about it. Rather this is a developer targeted
> message. Maybe a rewording of the messages be better? Something to also
> include consequences of the error?

I agree that a WARN may be a bit excessive here.

-- 
viresh