Re: [PATCH] cpufreq: scmi: Fix frequency invariance in slow path

Rafael J. Wysocki
2019-01-09T10:57:04Z

On Wednesday, January 9, 2019 11:45:11 AM CET Viresh Kumar wrote:
> On 09-01-19, 10:42, Quentin Perret wrote:
> > The scmi-cpufreq driver calls the arch_set_freq_scale() callback on
> > frequency changes to provide scale-invariant load-tracking signals to
> > the scheduler. However, in the slow path, it does so while specifying
> > the current and max frequencies in different units, hence resulting in a
> > broken freq_scale factor.
> >
> > Fix this by passing all frequencies in KHz, as stored in the CPUFreq
> > frequency table.
> >
> > Fixes: 99d6bdf33877 ("cpufreq: add support for CPU DVFS based on SCMI
> > message protocol")
> > Signed-off-by: Quentin Perret <quentin.perret@arm.com>
> > ---
> > drivers/cpufreq/scmi-cpufreq.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/cpufreq/scmi-cpufreq.c b/drivers/cpufreq/scmi-cpufreq.c
> > index 50b1551ba894..3f0693439486 100644
> > --- a/drivers/cpufreq/scmi-cpufreq.c
> > +++ b/drivers/cpufreq/scmi-cpufreq.c
> > @@ -52,9 +52,9 @@ scmi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
> > int ret;
> > struct scmi_data *priv = policy->driver_data;
> > struct scmi_perf_ops *perf_ops = handle->perf_ops;
> > - u64 freq = policy->freq_table[index].frequency * 1000;
> > + u64 freq = policy->freq_table[index].frequency;
> >
> > - ret = perf_ops->freq_set(handle, priv->domain_id, freq, false);
> > + ret = perf_ops->freq_set(handle, priv->domain_id, freq * 1000, false);
> > if (!ret)
> > arch_set_freq_scale(policy->related_cpus, freq,
> > policy->cpuinfo.max_freq);
>
> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

This would be stable-candidate I guess?