RE: [PATCH] cpufreq: Add Kryo CPU scaling driver

ilialin
2018-05-21T11:05:50Z

You are right.
cpu_dev_silver != cpu_dev_gold, and I found this with my tests as well.
Thank you.

> -----Original Message-----
> From: Russell King - ARM Linux <linux@armlinux.org.uk>
> Sent: Monday, May 21, 2018 13:54
> To: Ilia Lin <ilialin@codeaurora.org>
> Cc: viresh.kumar@linaro.org; devicetree@vger.kernel.org; linux-
> pm@vger.kernel.org; linux-arm-msm@vger.kernel.org; linux-
> kernel@vger.kernel.org; linux-soc@vger.kernel.org; linux-
> clk@vger.kernel.org; linux-arm-kernel@lists.infradead.org
> Subject: Re: [PATCH] cpufreq: Add Kryo CPU scaling driver
>
> On Mon, May 21, 2018 at 01:31:30PM +0300, Ilia Lin wrote:
> > +#define SILVER_LEAD 0
> > +#define GOLD_LEAD 2
>
> Okay, two different values here, but "GOLD_LEAD" appears unused.
>
> > + cpu_dev_silver = get_cpu_device(SILVER_LEAD);
> > + if (NULL == cpu_dev_silver)
> > + return -ENODEV;
> > +
> > + cpu_dev_gold = get_cpu_device(SILVER_LEAD);
> > + if (NULL == cpu_dev_gold)
> > + return -ENODEV;
>
> get_cpu_device() takes the logical CPU number. So the above gets CPU 0
> each time, and so cpu_dev_silver == cpu_dev_gold here. So what's the
> point of the second get_cpu_device() ? If it's supposed to be:
>
> cpu_dev_gold = get_cpu_device(GOLD_LEAD);
>
> That would get CPU 2, but in terms of these defines, it doesn't make that
> much sense. What exactly does "silver lead" and "gold lead" refer to in
these
> definitions?
>
> > + opp_silver =
> dev_pm_opp_set_supported_hw(cpu_dev_silver,&versions,1);
> > + if (IS_ERR(opp_silver)) {
> > + dev_err(cpu_dev_silver, "Failed to set supported
> hardware\n");
> > + ret = PTR_ERR(opp_silver);
> > + goto free_np;
> > + }
> > +
> > + opp_gold =
> dev_pm_opp_set_supported_hw(cpu_dev_gold,&versions,1);
> > + if (IS_ERR(opp_gold)) {
> > + dev_err(cpu_dev_gold, "Failed to set supported
> hardware\n");
> > + ret = PTR_ERR(opp_gold);
> > + goto free_opp_silver;
> > + }
>
> Given that cpu_dev_silver == cpu_dev_gold, doesn't the second call to
> dev_pm_opp_set_supported_hw() always fail, as opp_table-
> >supported_hw will be set by the first call?
>
> To me, this driver looks completely useless as it will always fail to
initialise,
> and I question whether this code has even been runtime tested.
>
> --
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