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Date:   Tue, 22 Dec 2020 14:42:55 +0530
From:   Viresh Kumar <viresh.kumar@linaro.org>
To:     Dmitry Osipenko <digetx@gmail.com>
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
Subject: Re: [PATCH v2 19/48] opp: Fix adding OPP entries in a wrong order if
 rate is unavailable
Message-ID: <20201222091255.wentz5hyt726qezg@vireshk-i7>
References: <20201217180638.22748-1-digetx@gmail.com>
 <20201217180638.22748-20-digetx@gmail.com>
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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.

>  		return opp1->rate < opp2->rate ? -1 : 1;
>  	if (opp1->bandwidth && opp2->bandwidth &&
>  	    opp1->bandwidth[0].peak != opp2->bandwidth[0].peak)
> @@ -1545,7 +1546,8 @@ int _opp_compare_key(struct dev_pm_opp *opp1, struct dev_pm_opp *opp2)
>  
>  static int _opp_is_duplicate(struct device *dev, struct dev_pm_opp *new_opp,
>  			     struct opp_table *opp_table,
> -			     struct list_head **head)
> +			     struct list_head **head,
> +			     bool rate_not_available)
>  {
>  	struct dev_pm_opp *opp;
>  	int opp_cmp;
> @@ -1559,13 +1561,13 @@ static int _opp_is_duplicate(struct device *dev, struct dev_pm_opp *new_opp,
>  	 * loop.
>  	 */
>  	list_for_each_entry(opp, &opp_table->opp_list, node) {
> -		opp_cmp = _opp_compare_key(new_opp, opp);
> +		opp_cmp = _opp_compare_key(new_opp, opp, rate_not_available);
>  		if (opp_cmp > 0) {
>  			*head = &opp->node;
>  			continue;
>  		}
>  
> -		if (opp_cmp < 0)
> +		if (opp_cmp < 0 || rate_not_available)
>  			return 0;

This shouldn't be required as well, isn't it ?

>  
>  		/* Duplicate OPPs */
> @@ -1601,12 +1603,11 @@ int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
>  	mutex_lock(&opp_table->lock);
>  	head = &opp_table->opp_list;
>  
> -	if (likely(!rate_not_available)) {
> -		ret = _opp_is_duplicate(dev, new_opp, opp_table, &head);
> -		if (ret) {
> -			mutex_unlock(&opp_table->lock);
> -			return ret;
> -		}
> +	ret = _opp_is_duplicate(dev, new_opp, opp_table, &head,
> +				rate_not_available);

This is the only thing we need to do here I believe.

> +	if (ret) {
> +		mutex_unlock(&opp_table->lock);
> +		return ret;
>  	}
>  
>  	list_add(&new_opp->node, head);
> diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h
> index 4ced7ffa8158..6f5be6c72f13 100644
> --- a/drivers/opp/opp.h
> +++ b/drivers/opp/opp.h
> @@ -219,7 +219,7 @@ struct opp_table *_find_opp_table(struct device *dev);
>  struct opp_device *_add_opp_dev(const struct device *dev, struct opp_table *opp_table);
>  struct dev_pm_opp *_opp_allocate(struct opp_table *opp_table);
>  void _opp_free(struct dev_pm_opp *opp);
> -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);
>  int _opp_add(struct device *dev, struct dev_pm_opp *new_opp, struct opp_table *opp_table, bool rate_not_available);
>  int _opp_add_v1(struct opp_table *opp_table, struct device *dev, unsigned long freq, long u_volt, bool dynamic);
>  void _dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask, int last_cpu);
> -- 
> 2.29.2

-- 
viresh