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>,
Peter Geis <pgwipeout@gmail.com>,
Nicolas Chauvet <kwizart@gmail.com>,
"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>, Nishanth Menon <nm@ti.com>,
Yangtao Li <tiny.windzz@gmail.com>,
Matt Merhar <mattmerhar@protonmail.com>,
linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org,
linux-pm@vger.kernel.org
Subject: Re: [PATCH v3 04/12] opp: Add dev_pm_opp_sync_regulators()
Date: Tue, 19 Jan 2021 10:28:27 +0530 [thread overview]
Message-ID: <20210119045827.2645gk6vabubehuh@vireshk-i7> (raw)
In-Reply-To: <4acde958-91c1-bbcb-6e20-2d90cf0e57d3@gmail.com>
On 18-01-21, 21:35, Dmitry Osipenko wrote:
> 18.01.2021 11:20, Viresh Kumar пишет:
> >> +int dev_pm_opp_sync_regulators(struct device *dev)
> >> +{
> >> + struct opp_table *opp_table;
> >> + struct regulator *reg;
> >> + int i, ret = 0;
> >> +
> >> + /* Device may not have OPP table */
> >> + opp_table = _find_opp_table(dev);
> >> + if (IS_ERR(opp_table))
> >> + return 0;
> >> +
> >> + /* Regulator may not be required for the device */
> >> + if (!opp_table->regulators)
> >> + goto put_table;
> >> +
> >> + mutex_lock(&opp_table->lock);
> > What exactly do you need this lock for ?
>
> It is needed for protecting simultaneous invocations of
> dev_pm_opp_sync_regulators() and dev_pm_opp_set_voltage().
>
> The sync_regulators() should be invoked only after completion of the
> set_voltage() in a case of Tegra power domain driver since potentially
> both could be running in parallel. For example device driver may be
> changing performance state in a work thread, while PM domain state is
> syncing.
I think just checking the 'enabled' flag should be enough here (you may need a
lock for it though, but the lock should cover only the area it is supposed to
cover and nothing else.
> But maybe it will be better to move the protection to the PM driver
> since we're focused on sync_regulators() and set_voltage() here, but
> there are other OPP API functions which use regulators. I'll need to
> take a closer look at it.
--
viresh
next prev parent reply other threads:[~2021-01-19 5:05 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-18 0:55 [PATCH v3 00/12] OPP API fixes and improvements Dmitry Osipenko
2021-01-18 0:55 ` [PATCH v3 01/12] opp: Fix adding OPP entries in a wrong order if rate is unavailable Dmitry Osipenko
2021-01-18 7:44 ` Viresh Kumar
2021-01-18 18:46 ` Dmitry Osipenko
2021-01-18 0:55 ` [PATCH v3 02/12] opp: Filter out OPPs based on availability of a required-OPP Dmitry Osipenko
2021-01-18 8:11 ` Viresh Kumar
2021-01-18 0:55 ` [PATCH v3 03/12] opp: Correct debug message in _opp_add_static_v2() Dmitry Osipenko
2021-01-18 8:14 ` Viresh Kumar
2021-01-18 0:55 ` [PATCH v3 04/12] opp: Add dev_pm_opp_sync_regulators() Dmitry Osipenko
2021-01-18 8:20 ` Viresh Kumar
2021-01-18 18:35 ` Dmitry Osipenko
2021-01-19 4:58 ` Viresh Kumar [this message]
2021-01-19 22:42 ` Dmitry Osipenko
2021-01-18 11:00 ` Viresh Kumar
2021-01-18 11:06 ` Viresh Kumar
2021-01-18 0:55 ` [PATCH v3 05/12] opp: Add dev_pm_opp_set_voltage() Dmitry Osipenko
2021-01-18 9:52 ` Viresh Kumar
2021-01-18 19:14 ` Dmitry Osipenko
2021-01-20 21:57 ` Dmitry Osipenko
2021-01-21 11:20 ` Viresh Kumar
2021-01-18 0:55 ` [PATCH v3 06/12] opp: Add dev_pm_opp_find_level_ceil() Dmitry Osipenko
2021-01-18 9:58 ` Viresh Kumar
2021-01-18 0:55 ` [PATCH v3 07/12] opp: Add dev_pm_opp_get_required_pstate() Dmitry Osipenko
2021-01-18 10:50 ` Viresh Kumar
2021-01-18 0:55 ` [PATCH v3 08/12] opp: Add devm_pm_opp_register_set_opp_helper Dmitry Osipenko
2021-01-18 11:07 ` Viresh Kumar
2021-01-18 0:55 ` [PATCH v3 09/12] opp: Add devm_pm_opp_attach_genpd Dmitry Osipenko
2021-01-18 11:14 ` Viresh Kumar
2021-01-18 0:55 ` [PATCH v3 10/12] opp: Support set_opp() customization without requiring to use regulators Dmitry Osipenko
2021-01-18 11:44 ` Viresh Kumar
2021-01-18 18:48 ` Dmitry Osipenko
2021-01-19 6:36 ` Viresh Kumar
2021-01-18 0:55 ` [PATCH v3 11/12] opp: Handle missing OPP table in dev_pm_opp_xlate_performance_state() Dmitry Osipenko
2021-01-18 11:18 ` Viresh Kumar
2021-01-18 0:55 ` [PATCH v3 12/12] opp: Print OPP level in debug message of _opp_add_static_v2() Dmitry Osipenko
2021-01-18 11:18 ` Viresh Kumar
2021-01-18 11:46 ` [PATCH v3 00/12] OPP API fixes and improvements Viresh Kumar
2021-01-19 17:35 ` Dmitry Osipenko
2021-01-20 15:41 ` Dmitry Osipenko
2021-01-21 7:51 ` Viresh Kumar
2021-01-21 20:30 ` Dmitry Osipenko
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