linux-kernel - Re: [PATCH 1/4] OPP: Add dev_pm_opp_xlate_performance

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Date:   Wed, 21 Nov 2018 11:36:22 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Rajendra Nayak <rnayak@...eaurora.org>
Cc:     ulf.hansson@...aro.org, Viresh Kumar <vireshk@...nel.org>,
        Nishanth Menon <nm@...com>, Stephen Boyd <sboyd@...nel.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>, linux-pm@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        niklas.cassel@...aro.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/4] OPP: Add dev_pm_opp_xlate_performance_state() helper

On 21-11-18, 10:47, Viresh Kumar wrote:
> On 21-11-18, 10:34, Rajendra Nayak wrote:
> > 
> > 
> > On 11/5/2018 12:06 PM, Viresh Kumar wrote:
> > > Introduce a new helper dev_pm_opp_xlate_performance_state() which will
> > > be used to translate from pstate of a device to another one.
> > > 
> > > Initially this will be used by genpd to find pstate of a master domain
> > > using its sub-domain's pstate.
> > > 
> > > Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> > > ---
> > >   drivers/opp/core.c     | 49 ++++++++++++++++++++++++++++++++++++++++++
> > >   include/linux/pm_opp.h |  7 ++++++
> > >   2 files changed, 56 insertions(+)
> > > 
> > > diff --git a/drivers/opp/core.c b/drivers/opp/core.c
> > > index 0eaa954b3f6c..010a4268e8dd 100644
> > > --- a/drivers/opp/core.c
> > > +++ b/drivers/opp/core.c
> > > @@ -1707,6 +1707,55 @@ void dev_pm_opp_put_genpd_virt_dev(struct opp_table *opp_table,
> > >   		dev_err(virt_dev, "Failed to find required device entry\n");
> > >   }
> > > +/**
> > > + * dev_pm_opp_xlate_performance_state() - Find required OPP's pstate for src_table.
> > > + * @src_table: OPP table which has dst_table as one of its required OPP table.
> > 
> > So I have a case where the src_table and dst_table are shared/same. Can you explain how would
> > it work in such a case?
> 
> Can you give the example, as I am finding some issues with such shared
> tables. Though the code may work just fine btw.

I may have found the problem you are facing here. Please try this diff
and tell me if you hitting it, check this in dmesg.

diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index 3740822b4197..6c45774306b0 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -225,6 +225,7 @@ static void _opp_table_alloc_required_tables(struct opp_table *opp_table,
 free_required_tables:
        _opp_table_free_required_tables(opp_table);
 put_np:
+       dev_err(dev, "Failed to allocate required OPP tables\n");
        of_node_put(np);
 }


-- 
viresh