linux-kernel - Re: [PATCH] cpufreq: cached_resolved

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Message-ID: <20200730064112.lvbwas7zzqruvprk@vireshk-mac-ubuntu>
Date:   Thu, 30 Jul 2020 12:11:12 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Amit Kucheria <amitk@...nel.org>
Cc:     Rafael Wysocki <rjw@...ysocki.net>, Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Linux PM list <linux-pm@...r.kernel.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        ionela.voinescu@....com,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] cpufreq: cached_resolved_idx can not be negative

On 30-07-20, 12:02, Amit Kucheria wrote:
> Looking at this more closely, I found another call site for
> cpufreq_frequency_table_target() in cpufreq.c that needs the index to
> be unsigned int.
> 
> But then cpufreq_frequency_table_target() returns -EINVAL, so we

It returns -EINVAL only in the case where the relation is not valid,
which will never happen. Maybe that should be marked with WARN or BUG
and we should drop return value of -EINVAL.

Rafael ?

> should be able to handle int values.

And so no.

> I think you will need to fix the unconditional assignment of
>     policy->cached_resolved_idx = idx
> in cpufreq_driver_resolve_freq(). It doesn't check for -EINVAL, so the
> qcom driver is write in checking for a negative value.

Right, I don't want it to have that check for the reason stated above.

The point is I don't want code that verifies cached-idx at all, it is
useless.

-- 
viresh