From: Joel Fernandes <joelaf@google.com>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Rafael Wysocki <rjw@rjwysocki.net>,
Peter Zijlstra <peterz@infradead.org>,
Linux PM <linux-pm@vger.kernel.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Steve Muckle <smuckle.linux@gmail.com>,
Juri Lelli <juri.lelli@arm.com>,
Morten Rasmussen <Morten.Rasmussen@arm.com>,
Patrick Bellasi <patrick.bellasi@arm.com>,
eas-dev@lists.linaro.org,
Saravana Kannan <skannan@codeaurora.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH V5 2/2] cpufreq: Process remote callbacks from any CPU if the platform permits
Date: Fri, 28 Jul 2017 20:43:22 -0700 [thread overview]
Message-ID: <CAJWu+ooWDUigT8zck1Q24oSLETf8mhSLj0-k+9RB32pzEDQPjw@mail.gmail.com> (raw)
In-Reply-To: <c121a20eff05565155852c070e83504bf117da3e.1501223897.git.viresh.kumar@linaro.org>
On Thu, Jul 27, 2017 at 11:46 PM, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> On many platforms, CPUs can do DVFS across cpufreq policies. i.e CPU
> from policy-A can change frequency of CPUs belonging to policy-B.
>
> This is quite common in case of ARM platforms where we don't
> configure any per-cpu register.
>
> Add a flag to identify such platforms and update
> cpufreq_can_do_remote_dvfs() to allow remote callbacks if this flag is
> set.
>
> Also enable the flag for cpufreq-dt driver which is used only on ARM
> platforms currently.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
> drivers/cpufreq/cpufreq-dt.c | 1 +
> include/linux/cpufreq.h | 18 ++++++++++++++++--
> 2 files changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c
> index fef3c2160691..d83ab94d041a 100644
> --- a/drivers/cpufreq/cpufreq-dt.c
> +++ b/drivers/cpufreq/cpufreq-dt.c
> @@ -274,6 +274,7 @@ static int cpufreq_init(struct cpufreq_policy *policy)
> transition_latency = CPUFREQ_ETERNAL;
>
> policy->cpuinfo.transition_latency = transition_latency;
> + policy->dvfs_possible_from_any_cpu = true;
>
Are there also ARM hardware that may not support it? If yes, wouldn't
a saner thing to do be to keep default as false and read the property
from DT for hardware that does support it and then set to true?
thanks,
-Joel
next prev parent reply other threads:[~2017-07-29 3:43 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-28 6:46 [PATCH V5 0/2] sched: cpufreq: Allow remote callbacks Viresh Kumar
2017-07-28 6:46 ` [PATCH V5 1/2] sched: cpufreq: Allow remote cpufreq callbacks Viresh Kumar
2017-07-31 21:19 ` Saravana Kannan
2017-07-28 6:46 ` [PATCH V5 2/2] cpufreq: Process remote callbacks from any CPU if the platform permits Viresh Kumar
2017-07-29 3:43 ` Joel Fernandes [this message]
2017-07-31 4:00 ` Viresh Kumar
2017-07-31 21:20 ` Saravana Kannan
2017-08-01 11:00 ` [Eas-dev] " Pavan Kondeti
2017-08-02 3:44 ` Viresh Kumar
2017-08-01 12:01 ` [PATCH V5 0/2] sched: cpufreq: Allow remote callbacks Peter Zijlstra
2017-08-01 23:22 ` Rafael J. Wysocki
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