From: Ulf Hansson <ulf.hansson@linaro.org>
To: Dmitry Osipenko <digetx@gmail.com>
Cc: "Rafael J . Wysocki" <rjw@rjwysocki.net>,
Viresh Kumar <viresh.kumar@linaro.org>,
Linux PM <linux-pm@vger.kernel.org>,
Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
Jonathan Hunter <jonathanh@nvidia.com>,
Thierry Reding <thierry.reding@gmail.com>,
Rajendra Nayak <rnayak@codeaurora.org>,
Stephan Gerhold <stephan@gerhold.net>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/3] PM: domains: Drop the performance state vote for a device at detach
Date: Thu, 9 Sep 2021 16:45:38 +0200 [thread overview]
Message-ID: <CAPDyKFoV9MOUvu0GLyW-WmNzXbGyFomcug9aTEB-pH32gRHYnQ@mail.gmail.com> (raw)
In-Reply-To: <71618f83-de5b-1180-60f4-8561c4f655a9@gmail.com>
On Thu, 9 Sept 2021 at 15:48, Dmitry Osipenko <digetx@gmail.com> wrote:
>
> 07.09.2021 13:16, Ulf Hansson пишет:
> ...
> >>> Also note that a very similar problem exists, *before* the device gets
> >>> attached in the first place. More precisely, nothing prevents the
> >>> performance state from being set to a non-compatible value for an
> >>> always-on HW/device that hasn't been attached yet. So maybe you need
> >>> to set the maximum performance state at genpd initializations, then
> >>> use the ->sync_state() callback to very that all consumers have been
> >>> attached to the genpd provider, before allowing the state to be
> >>> changed/lowered?
> >>
> >> That is already done by the PD driver.
> >>
> >> https://elixir.bootlin.com/linux/latest/source/drivers/soc/tegra/pmc.c#L3790
> >
> > Yes, I already knew that, but forgot it. :-) Thanks for the pointer.
> > Let me rethink the approach.
> >
> > In a way, it kind of sounds like this is a generic problem - so
> > perhaps we should think of adding a ->withdraw_sync_state() callback
> > that can be assigned by provider drivers, to get informed when a
> > consumer driver is getting unbinded.
>
> Not sure, doesn't feel to me that this is necessary for today. A bit too
> cumbersome for a simple sanity-check, IMO.
Maybe, but I can bring it up with the fw_devlinks people to see what they think.
In any case, we should not move forward with $subject patch as is.
Let me think about it.
Kind regards
Uffe
next prev parent reply other threads:[~2021-09-09 14:48 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-02 10:16 [PATCH 0/3] PM: domains: Improvements for performance states in genpd Ulf Hansson
2021-09-02 10:16 ` [PATCH 1/3] PM: domains: Drop the performance state vote for a device at detach Ulf Hansson
2021-09-03 6:01 ` Dmitry Osipenko
2021-09-03 8:22 ` Ulf Hansson
2021-09-03 9:58 ` Dmitry Osipenko
2021-09-03 14:03 ` Ulf Hansson
2021-09-05 8:26 ` Dmitry Osipenko
2021-09-06 10:24 ` Ulf Hansson
2021-09-06 14:11 ` Dmitry Osipenko
2021-09-06 17:34 ` Ulf Hansson
2021-09-06 19:33 ` Dmitry Osipenko
2021-09-07 10:16 ` Ulf Hansson
2021-09-09 13:48 ` Dmitry Osipenko
2021-09-09 14:45 ` Ulf Hansson [this message]
2021-09-02 10:16 ` [PATCH 2/3] PM: domains: Restructure some code in __genpd_dev_pm_attach() Ulf Hansson
2021-09-02 10:16 ` [PATCH 3/3] PM: domains: Add a ->dev_get_performance_state() callback to genpd Ulf Hansson
2021-09-03 6:00 ` Dmitry Osipenko
2021-09-03 8:55 ` Ulf Hansson
2021-09-03 10:06 ` Dmitry Osipenko
2021-09-03 14:09 ` Ulf Hansson
2021-09-05 9:11 ` Dmitry Osipenko
2021-09-06 10:53 ` Ulf Hansson
2021-09-06 14:35 ` Dmitry Osipenko
2021-09-07 3:40 ` Viresh Kumar
2021-09-07 8:10 ` Dmitry Osipenko
2021-09-07 9:57 ` Ulf Hansson
2021-09-09 13:48 ` Dmitry Osipenko
2021-09-09 14:39 ` Ulf Hansson
2021-09-10 11:24 ` Dmitry Osipenko
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