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From: Sudeep Holla <sudeep.holla@arm.com>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com>,
	rjw@rjwysocki.net, guohanjun@huawei.com, ionela.voinescu@arm.com,
	linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [Question]: about 'cpuinfo_cur_freq' shown in sysfs when the CPU is in idle state
Date: Wed, 3 Jun 2020 11:40:17 +0100	[thread overview]
Message-ID: <20200603104017.GD7259@bogus> (raw)
In-Reply-To: <20200603102159.hzctwiqiukwhrpo7@vireshk-i7>

On Wed, Jun 03, 2020 at 03:51:59PM +0530, Viresh Kumar wrote:
> On 03-06-20, 11:17, Sudeep Holla wrote:
> > On Wed, Jun 03, 2020 at 03:40:10PM +0530, Viresh Kumar wrote:
> > > On 03-06-20, 11:07, Sudeep Holla wrote:
> > > > But I have another question. If we can detect that CPPC on some platforms
> > > > rely on CPU registers(I assume FFH registers here and not system/io/...
> > > > type of GAS registers), can we set dvfs_on_any_cpu(can't recall exact
> > > > flag name) to false if not already done to prevent such issues. Or I am
> > > > talking non-sense as it may be applicable only for _set operation and
> > >
> > >           Yes, non-sense :)
> > >
> >
> > Thanks for confirming 👍.
>
> Hehe.
>
> So, do you agree that we better do the read from the CPUs themselves ?
>

Yes if that is fine. I thought waking up the core was not a good solution
in terms of power, but I have no objection for that as well as return 0
as IMO it aligns with the AMU counters when CPU is idle.

--
Regards,
Sudeep

  reply	other threads:[~2020-06-03 10:40 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-02  3:34 [Question]: about 'cpuinfo_cur_freq' shown in sysfs when the CPU is in idle state Xiongfeng Wang
2020-06-03  2:05 ` Hanjun Guo
2020-06-03  7:52 ` Viresh Kumar
2020-06-03 10:07   ` Sudeep Holla
2020-06-03 10:10     ` Viresh Kumar
2020-06-03 10:17       ` Sudeep Holla
2020-06-03 10:21         ` Viresh Kumar
2020-06-03 10:40           ` Sudeep Holla [this message]
2020-06-03 13:39   ` Rafael J. Wysocki
2020-06-04  1:32     ` Xiongfeng Wang
2020-06-04  4:41       ` Viresh Kumar
2020-06-04 10:42         ` Rafael J. Wysocki
2020-06-04 12:58           ` Sudeep Holla
2020-06-10  9:40             ` Ionela Voinescu
2020-06-11  1:52               ` Xiongfeng Wang
2020-06-12 11:55                 ` Rafael J. Wysocki

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