linux-kernel - Re: [PATCH] power: Print wakeup_count instead of event

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Date:   Thu, 7 Jun 2018 09:47:24 -0700
From:   Ravi Chandra Sadineni <ravisadineni@...gle.com>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Ravi Chandra Sadineni <ravisadineni@...omium.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>, chenhong3@...wei.com,
        Pavel Machek <pavel@....cz>, Dmitry Torokhov <dtor@...gle.com>,
        Len Brown <len.brown@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Todd Broch <tbroch@...gle.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        Rajat Jain <rajatja@...gle.com>,
        Benson Leung <bleung@...gle.com>
Subject: Re: [PATCH] power: Print wakeup_count instead of event_count in the
 sysfs attribute.

Hi Rafeal,

Soft ping. Is this patch good to be merged ?

Thanks,
Ravi


On Sun, Jun 3, 2018 at 10:14 AM, Ravi Chandra Sadineni
<ravisadineni@...gle.com> wrote:
> Hi Rafael,
>
> On Sun, Jun 3, 2018 at 1:05 AM, Rafael J. Wysocki <rafael@...nel.org> wrote:
>> On Sat, Jun 2, 2018 at 4:32 AM, Ravi Chandra Sadineni
>> <ravisadineni@...omium.org> wrote:
>>> Currently we show event_count instead of wakeup_count as part of per
>>> device wakeup_count sysfs attribute. Change it to wakeup_count to make
>>> it more meaningful.
>>
>> More information, please.
>>
>> In particular, why it is more meaningful.
> Wakeup_count increments only when events_check_enabled is set. This
> bool is set whenever we write current wakeup count to
> /sys/power/wakeup_count from the user land. Also events_check_enabled
> is cleared on every resume. My understanding is that, userland is
> expected to write to this just before suspend. This way
> pm_wakeup_event() when called from irqs will increment the
> wakeup_count only if we are in system wide suspend resume cycle and
> should give a fair approximation of how many times a device might have
> caused a wake from S3/S0iX.  event_count on the other hand will
> increment every time pm_wakeup_event() is called irrespective of
> whether we are in a suspend/resume cycle.  For example when I try
> doing something like this (https://lkml.org/lkml/2018/6/1/890), we see
> the wakeup_count sysfs attribute for the particular device
> incrementing every time there is a irq. If it is important to expose
> event_count via sysfs attribute, should we create another attribute ?
> Also we do expose each of these counters via
> debugfs(/sys/kernel/debug/wake_sources).
>
> Please correct me if I am wrong or missing something. Also if there is
> a better way to do this, please let me know.
>>
>> Thanks,
>> Rafael