linux-kernel - Re: [PATCH v3 3/5] OPP: Improve require-opps linking

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Date:   Tue, 30 Jul 2019 16:05:43 -0700
From:   Saravana Kannan <saravanak@...gle.com>
To:     Hsin-Yi Wang <hsinyi@...omium.org>
Cc:     MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...nel.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Sibi Sankar <sibis@...eaurora.org>,
        Android Kernel Team <kernel-team@...roid.com>,
        Linux PM <linux-pm@...r.kernel.org>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 3/5] OPP: Improve require-opps linking

On Tue, Jul 30, 2019 at 4:03 PM Hsin-Yi Wang <hsinyi@...omium.org> wrote:
>
> On Wed, Jul 17, 2019 at 10:23 PM Saravana Kannan <saravanak@...gle.com> wrote:
>
> > -free_required_tables:
> > -       _opp_table_free_required_tables(opp_table);
> > -put_np:
> > -       of_node_put(np);
> > +       for (i = 0; i < src->required_opp_count; i++) {
> > +               if (src->required_opp_tables[i])
> > +                       continue;
> > +
> > +               req_np = of_parse_required_opp(src_opp->np, i);
> > +               if (!req_np)
> > +                       continue;
> > +
> > +               req_table = _find_table_of_opp_np(req_np);
> Not yet tested in v4, but in v3:
> In _find_table_of_opp_np(), there's a lockdep check:
> lockdep_assert_held(&opp_table_lock);
> which would lead to lockdep warnings.
>
> Call trace:
> _find_table_of_opp_np
> _of_lazy_link_required_tables
> dev_pm_opp_xlate_opp

Thanks for testing. I'll keep this in mind based on where the rest of
the discussion goes.

-Saravana