From: Leo Yan <leo.yan@linaro.org>
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: Jonathan Corbet <corbet@lwn.net>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Wei Xu <xuwei5@hisilicon.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Andy Gross <andy.gross@linaro.org>,
David Brown <david.brown@linaro.org>,
Michael Turquette <mturquette@baylibre.com>,
Stephen Boyd <sboyd@codeaurora.org>,
Mathieu Poirier <mathieu.poirier@linaro.org>,
Guodong Xu <guodong.xu@linaro.org>,
John Stultz <john.stultz@linaro.org>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org,
linux-clk@vger.kernel.org, mike.leach@linaro.org,
Suzuki.Poulose@arm.com
Subject: Re: [PATCH v5 6/9] coresight: add support for CPU debug module
Date: Fri, 31 Mar 2017 08:54:20 +0800 [thread overview]
Message-ID: <20170331005420.GA6149@leoy-linaro> (raw)
In-Reply-To: <f0c460e2-4e49-4f34-5288-f20a519dc182@arm.com>
On Thu, Mar 30, 2017 at 04:56:52PM +0100, Sudeep Holla wrote:
[...]
> > +static struct pm_qos_request debug_qos_req;
> > +static int idle_constraint = PM_QOS_DEFAULT_VALUE;
> > +module_param(idle_constraint, int, 0600);
> > +MODULE_PARM_DESC(idle_constraint, "Latency requirement in microseconds for CPU "
> > + "idle states (default is -1, which means have no limiation "
> > + "to CPU idle states; 0 means disabling all idle states; user "
> > + "can choose other platform dependent values so can disable "
> > + "specific idle states for the platform)");
> > +
>
> NACK for this. Why you want the policy inside the driver. You can always
> do that from the user-space. I have mentioned it several times now.
> What can't you do these ?
>
> 1. echo "what_ever_latency_you_need_in_uS" > /dev/cpu_dma_latency
> 2. echo 1 > /sys/devices/system/cpu/cpu$cpu/cpuidle/state$state/disable
> (for all cpus and their states) (1) is definitely simpler way to
> disable deeper idle if latency = 0uS
>
> You can always warn user about that when it's enabled via debugfs/sysfs
Thanks for suggestion, now it's clear for me.
> --
> Regards,
> Sudeep
next prev parent reply other threads:[~2017-03-31 0:54 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-25 18:23 [PATCH v5 0/9] coresight: enable debug module Leo Yan
2017-03-25 18:23 ` [PATCH v5 1/9] coresight: bindings for CPU " Leo Yan
2017-03-30 22:49 ` Rob Herring
2017-03-31 9:04 ` Suzuki K Poulose
2017-03-25 18:23 ` [PATCH v5 2/9] doc: Add documentation for Coresight CPU debug Leo Yan
2017-03-25 18:23 ` [PATCH v5 3/9] coresight: of_get_coresight_platform_data: Add missing of_node_put Leo Yan
2017-03-25 18:23 ` [PATCH v5 4/9] coresight: refactor with function of_coresight_get_cpu Leo Yan
2017-03-31 9:05 ` Suzuki K Poulose
[not found] ` <1490466197-29163-1-git-send-email-leo.yan-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2017-03-25 18:23 ` [PATCH v5 5/9] coresight: use const for device_node structures Leo Yan
[not found] ` <1490466197-29163-6-git-send-email-leo.yan-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2017-04-04 21:48 ` Stephen Boyd
2017-03-25 18:23 ` [PATCH v5 9/9] arm64: dts: qcom: msm8916: Add debug unit Leo Yan
2017-03-25 18:23 ` [PATCH v5 6/9] coresight: add support for CPU debug module Leo Yan
2017-03-27 16:34 ` Suzuki K Poulose
2017-03-29 3:07 ` Leo Yan
2017-03-29 9:07 ` Suzuki K Poulose
2017-03-29 10:27 ` Leo Yan
2017-03-29 10:31 ` Suzuki K Poulose
[not found] ` <89b6c6c7-0da0-6891-312a-c9221851c20a-5wv7dgnIgG8@public.gmane.org>
2017-03-29 10:37 ` Leo Yan
2017-03-29 15:50 ` Suzuki K Poulose
2017-03-29 15:17 ` Mike Leach
2017-03-30 1:18 ` Leo Yan
2017-03-29 15:41 ` Mathieu Poirier
2017-03-28 16:50 ` Mathieu Poirier
2017-03-29 1:54 ` Leo Yan
2017-03-29 14:56 ` Mike Leach
2017-03-30 1:03 ` Leo Yan
2017-03-30 9:00 ` Suzuki K Poulose
2017-03-30 13:51 ` Leo Yan
2017-03-30 15:47 ` Sudeep Holla
2017-03-29 16:55 ` Mathieu Poirier
[not found] ` <20170329165535.GB24889-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2017-03-30 1:59 ` Leo Yan
2017-03-30 15:46 ` Mathieu Poirier
[not found] ` <CANLsYkwPYSvy2xjf8uuvx1WGWpGdMFy7kF=30VbvgW+jDvnFuw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-03-30 16:04 ` Sudeep Holla
[not found] ` <1490466197-29163-7-git-send-email-leo.yan-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2017-03-30 15:56 ` Sudeep Holla
2017-03-31 0:54 ` Leo Yan [this message]
2017-03-25 18:23 ` [PATCH v5 7/9] clk: hi6220: add debug APB clock Leo Yan
2017-04-04 21:51 ` Stephen Boyd
[not found] ` <20170404215109.GH18246-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
2017-04-06 13:59 ` Leo Yan
2017-03-25 18:23 ` [PATCH v5 8/9] arm64: dts: hi6220: register debug module Leo Yan
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