linux-kernel - Re: [PATCH v4 1/2] cpufreq: tegra124: Remove use of disable

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CALHNRZ8Ri4sv7JkFj6t8b3VT=LU9ZS0Wc_8US2b3xGimLY6P6g@mail.gmail.com>
Date: Wed, 14 May 2025 11:26:06 -0500
From: Aaron Kling <webgeek1234@...il.com>
To: Jon Hunter <jonathanh@...dia.com>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>, Viresh Kumar <viresh.kumar@...aro.org>, 
	Thierry Reding <thierry.reding@...il.com>, linux-pm@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-tegra@...r.kernel.org
Subject: Re: [PATCH v4 1/2] cpufreq: tegra124: Remove use of disable_cpufreq

On Fri, May 9, 2025 at 11:57 AM Aaron Kling <webgeek1234@...il.com> wrote:
>
> On Fri, May 9, 2025 at 6:04 AM Jon Hunter <jonathanh@...dia.com> wrote:
> >
> >
> >
> > On 09/05/2025 01:04, Aaron Kling via B4 Relay wrote:
> > > From: Aaron Kling <webgeek1234@...il.com>
> > >
> > > Instead, unregister the cpufreq device for this fatal fail case.
> >
> > This is not a complete sentence. Seems to be a continuation of the
> > subject which is not clear to the reader (at least not to me). No
> > mention of why or what this is fixing, if anything?
>
> I can clean up the subject and message in a new revision. More on the
> reasoning below.
>
> > >
> > > Signed-off-by: Aaron Kling <webgeek1234@...il.com>
> > > ---
> > >   drivers/cpufreq/tegra124-cpufreq.c | 5 ++++-
> > >   1 file changed, 4 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/cpufreq/tegra124-cpufreq.c b/drivers/cpufreq/tegra124-cpufreq.c
> > > index 514146d98bca2d8aa59980a14dff3487cd8045f6..bc0691e8971f9454def37f489e4a3e244100b9f4 100644
> > > --- a/drivers/cpufreq/tegra124-cpufreq.c
> > > +++ b/drivers/cpufreq/tegra124-cpufreq.c
> > > @@ -168,7 +168,10 @@ static int __maybe_unused tegra124_cpufreq_resume(struct device *dev)
> > >   disable_dfll:
> > >       clk_disable_unprepare(priv->dfll_clk);
> > >   disable_cpufreq:
> > > -     disable_cpufreq();
> > > +     if (!IS_ERR(priv->cpufreq_dt_pdev)) {
> > > +             platform_device_unregister(priv->cpufreq_dt_pdev);
> > > +             priv->cpufreq_dt_pdev = ERR_PTR(-ENODEV);
> > > +     }
> >
> > So you are proposing to unregister the device in resume? That seems odd.
> > I see there is no remove for this driver, but I really don't see the
> > value in this.
>
> This was suggested by Viresh in v1 [0] to replace the call to
> disable_cpufreq, which is not currently an exported function. I'm open
> to other suggestions.
>
> Sincerely,
> Aaron
>
> [0] https://lore.kernel.org/all/20250421054452.fdlrrhtsimyucbup@vireshk-i7/

Viresh, could you comment here please? As you were the one that
suggested replacing disable_cpufreq with an unregister instead of
exporting said function. I can make the code changes and verify they
work as intended, but I'm not familiar enough with this subsystem to
know what a good option here is. Are there any other cpufreq drivers
that have to handle a resume failure like this?

Sincerely,
Aaron