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Subject: Re: [PATCH v2 19/48] opp: Fix adding OPP entries in a wrong order if
 rate is unavailable
To:     Viresh Kumar <viresh.kumar@linaro.org>
Cc:     Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Mark Brown <broonie@kernel.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Peter Geis <pgwipeout@gmail.com>,
        Nicolas Chauvet <kwizart@gmail.com>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Kevin Hilman <khilman@kernel.org>,
        Peter De Schrijver <pdeschrijver@nvidia.com>,
        Viresh Kumar <vireshk@kernel.org>,
        Stephen Boyd <sboyd@kernel.org>,
        Michael Turquette <mturquette@baylibre.com>,
        devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org,
        linux-media@vger.kernel.org, linux-tegra@vger.kernel.org,
        linux-clk@vger.kernel.org
References: <20201217180638.22748-1-digetx@gmail.com>
 <20201217180638.22748-20-digetx@gmail.com>
 <20201222091255.wentz5hyt726qezg@vireshk-i7>
From:   Dmitry Osipenko <digetx@gmail.com>
Message-ID: <db6273e6-8406-b7ae-b51d-48ceb6d21962@gmail.com>
Date:   Tue, 22 Dec 2020 22:19:26 +0300
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22.12.2020 12:12, Viresh Kumar пишет:
> On 17-12-20, 21:06, Dmitry Osipenko wrote:
>> Fix adding OPP entries in a wrong (opposite) order if OPP rate is
>> unavailable. The OPP comparison is erroneously skipped if OPP rate is
>> missing, thus OPPs are left unsorted.
>>
>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>> ---
>>  drivers/opp/core.c | 23 ++++++++++++-----------
>>  drivers/opp/opp.h  |  2 +-
>>  2 files changed, 13 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/opp/core.c b/drivers/opp/core.c
>> index 34f7e530d941..5c7f130a8de2 100644
>> --- a/drivers/opp/core.c
>> +++ b/drivers/opp/core.c
>> @@ -1531,9 +1531,10 @@ static bool _opp_supported_by_regulators(struct dev_pm_opp *opp,
>>  	return true;
>>  }
>>  
>> -int _opp_compare_key(struct dev_pm_opp *opp1, struct dev_pm_opp *opp2)
>> +int _opp_compare_key(struct dev_pm_opp *opp1, struct dev_pm_opp *opp2,
>> +		     bool rate_not_available)
>>  {
>> -	if (opp1->rate != opp2->rate)
>> +	if (!rate_not_available && opp1->rate != opp2->rate)
> 
> rate will be 0 for both the OPPs here if rate_not_available is true and so this
> change shouldn't be required.

The rate_not_available is negated in the condition. This change is
required because both rates are 0 and then we should proceed to the
levels comparison.

I guess it's not clear by looking at this patch, please see a full
version of the function:

int _opp_compare_key(struct dev_pm_opp *opp1, struct dev_pm_opp *opp2,
         bool rate_not_available)
{
  if (!rate_not_available && opp1->rate != opp2->rate)
    return opp1->rate < opp2->rate ? -1 : 1;
  if (opp1->bandwidth && opp2->bandwidth &&
      opp1->bandwidth[0].peak != opp2->bandwidth[0].peak)
    return opp1->bandwidth[0].peak < opp2->bandwidth[0].peak ? -1 : 1;
  if (opp1->level != opp2->level)
    return opp1->level < opp2->level ? -1 : 1;
  return 0;
}

Perhaps we could check whether opp1->rate=0, like it's done for the
opp1->bandwidth. I'll consider this variant for v3, thanks.