From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Tri Vo <trong@android.com>
Cc: Tony Lindgren <tony@atomide.com>,
Stephen Boyd <swboyd@chromium.org>, Qian Cai <cai@lca.pw>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Linux PM <linux-pm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: "PM / wakeup: Show wakeup sources stats in sysfs" causes boot warnings
Date: Fri, 16 Aug 2019 14:17:23 +0200 [thread overview]
Message-ID: <CAJZ5v0hY8=0j=heXuAS-5cBafDSE8ZakLDW4NGCjAbxUAt3j4Q@mail.gmail.com> (raw)
In-Reply-To: <CANA+-vDeSAYUNfTQzQPT2N_CUgvYr6i_LP_BdHT_zX+FPt8NHg@mail.gmail.com>
On Wed, Aug 14, 2019 at 8:37 PM Tri Vo <trong@android.com> wrote:
>
> On Wed, Aug 14, 2019 at 1:40 AM Tony Lindgren <tony@atomide.com> wrote:
> >
> > * Stephen Boyd <swboyd@chromium.org> [691231 23:00]:
> > > I also notice that device_set_wakeup_capable() has a check to see if the
> > > device is registered yet and it skips creating sysfs entries for the
> > > device if it isn't created in sysfs yet. Why? Just so it can be called
> > > before the device is created? I guess the same logic is handled by
> > > dpm_sysfs_add() if the device is registered after calling
> > > device_set_wakeup_*().
> >
> > Hmm just guessing.. It's maybe because drivers can enable and disable
> > the wakeup capability at any point for example like driver/net drivers
> > do based on WOL etc?
> >
> > > There's two approaches I see:
> > >
> > > 1) Do a similar check for device_set_wakeup_enable() and skip
> > > adding the wakeup class until dpm_sysfs_add().
> > >
> > > 2) Find each case where this happens and only call wakeup APIs
> > > on the device after the device is added.
> > >
> > > I guess it's better to let devices have wakeup modified on them before
> > > they're registered with the device core?
> >
> > I think we should at least initially handle case #1 above as multiple
> > places otherwise seem to break. Then maybe we could add a warning to
> > help fix all the #2 cases if needed?
>
> Makes sense. For case#1, we could also just register the wakeup source
> without specifying the parent device if the latter hasn't been
> registered yet. Userspace won't be able to associate a wakeup source
> to the parent device. But I think it's a reasonable fix, assuming we
> want to fix devices not being added before calling wakeup APIs #2.
Well, OK
I'm going to drop the entire series from linux-next at this point and
let's start over.
Also note that all of this is not an issue until we start to add
children under the device passed to device_set_wakeup_enable() and
friends so maybe that is not a good idea after all?
next prev parent reply other threads:[~2019-08-16 12:17 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-13 21:32 "PM / wakeup: Show wakeup sources stats in sysfs" causes boot warnings Qian Cai
2019-08-13 22:35 ` Stephen Boyd
2019-08-13 23:04 ` Tri Vo
2019-08-13 23:10 ` Rafael J. Wysocki
2019-08-14 13:18 ` Qian Cai
2019-08-14 0:35 ` Stephen Boyd
2019-08-14 7:03 ` Stephen Boyd
2019-08-14 8:40 ` Tony Lindgren
2019-08-14 18:37 ` Tri Vo
2019-08-16 12:17 ` Rafael J. Wysocki [this message]
2019-08-16 14:19 ` Stephen Boyd
2019-08-19 9:33 ` Rafael J. Wysocki
2019-08-14 15:19 ` Dmitry Torokhov
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