linux-kernel - Re: [PATCH 04/19] cpufreq: amd: introduce a new amd pstate driver to support future processors

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Date:   Mon, 13 Sep 2021 19:55:05 +0800
From:   Huang Rui <ray.huang@....com>
To:     Peter Zijlstra <peterz@...radead.org>
CC:     "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Shuah Khan <skhan@...uxfoundation.org>,
        "Borislav Petkov" <bp@...e.de>, Ingo Molnar <mingo@...nel.org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "Sharma, Deepak" <Deepak.Sharma@....com>,
        "Deucher, Alexander" <Alexander.Deucher@....com>,
        "Limonciello, Mario" <Mario.Limonciello@....com>,
        "Fontenot, Nathan" <Nathan.Fontenot@....com>,
        "Su, Jinzhou (Joe)" <Jinzhou.Su@....com>,
        "Du, Xiaojian" <Xiaojian.Du@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>
Subject: Re: [PATCH 04/19] cpufreq: amd: introduce a new amd pstate driver to
 support future processors

On Thu, Sep 09, 2021 at 11:03:54PM +0800, Peter Zijlstra wrote:
> On Wed, Sep 08, 2021 at 10:59:46PM +0800, Huang Rui wrote:
> 
> > +static int pstate_init_perf(struct amd_cpudata *cpudata)
> > +{
> > +	u64 cap1;
> > +
> > +	int ret = rdmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1,
> > +				     &cap1);
> > +	if (ret)
> > +		return ret;
> > +
> > +	/* Some AMD processors has specific power features that the cppc entry
> > +	 * doesn't indicate the highest performance. It will introduce the
> > +	 * feature in following days.
> > +	 */
> 
> Wrong comment style; also imagine reading this comment half a year from
> now...

How about use a "TODO" to indicate the next step here?

Thanks,
Ray

> 
> > +	WRITE_ONCE(cpudata->highest_perf, amd_get_highest_perf());
> > +
> > +	WRITE_ONCE(cpudata->nominal_perf, CAP1_NOMINAL_PERF(cap1));
> > +	WRITE_ONCE(cpudata->lowest_nonlinear_perf, CAP1_LOWNONLIN_PERF(cap1));
> > +	WRITE_ONCE(cpudata->lowest_perf, CAP1_LOWEST_PERF(cap1));
> > +
> > +	return 0;
> > +}