linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Saravana Kannan <saravanak@google.com>
To: Rob Herring <robh@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Linus Walleij <linus.walleij@linaro.org>,
	Will Deacon <will@kernel.org>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Kevin Hilman <khilman@kernel.org>,
	Thierry Reding <treding@nvidia.com>,
	Mark Brown <broonie@kernel.org>, Pavel Machek <pavel@ucw.cz>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
	Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
	"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
	"open list:THERMAL" <linux-pm@vger.kernel.org>,
	Linux IOMMU <iommu@lists.linux-foundation.org>,
	Android Kernel Team <kernel-team@android.com>,
	Linux Doc Mailing List <linux-doc@vger.kernel.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1] driver core: Extend deferred probe timeout on driver registration
Date: Fri, 13 May 2022 10:25:52 -0700	[thread overview]
Message-ID: <CAGETcx8=ZX+Pb4ioMVb7LfuF9c3HNP8g1+WMqZR=Pq7-9=DUCA@mail.gmail.com> (raw)
In-Reply-To: <CAL_Jsq+2A7mRVV24XW0YcP8GkFCK_Ri4KDcqvW4e0p3TkQMWVg@mail.gmail.com>

On Fri, May 13, 2022 at 6:58 AM Rob Herring <robh@kernel.org> wrote:
>
> On Fri, Apr 29, 2022 at 5:09 PM Saravana Kannan <saravanak@google.com> wrote:
> >
> > The deferred probe timer that's used for this currently starts at
> > late_initcall and runs for driver_deferred_probe_timeout seconds. The
> > assumption being that all available drivers would be loaded and
> > registered before the timer expires. This means, the
> > driver_deferred_probe_timeout has to be pretty large for it to cover the
> > worst case. But if we set the default value for it to cover the worst
> > case, it would significantly slow down the average case. For this
> > reason, the default value is set to 0.
> >
> > Also, with CONFIG_MODULES=y and the current default values of
> > driver_deferred_probe_timeout=0 and fw_devlink=on, devices with missing
> > drivers will cause their consumer devices to always defer their probes.
> > This is because device links created by fw_devlink defer the probe even
> > before the consumer driver's probe() is called.
> >
> > Instead of a fixed timeout, if we extend an unexpired deferred probe
> > timer on every successful driver registration, with the expectation more
> > modules would be loaded in the near future, then the default value of
> > driver_deferred_probe_timeout only needs to be as long as the worst case
> > time difference between two consecutive module loads.
> >
> > So let's implement that and set the default value to 10 seconds when
> > CONFIG_MODULES=y.
>
> We had to revert a non-zero timeout before (issue with NFS root IIRC).
> Does fw_devlink=on somehow fix that?

If it's the one where ip autoconfig was timing out, then John Stultz
fixed it by fixing wait_for_device_probe().
https://lore.kernel.org/all/20200422203245.83244-4-john.stultz@linaro.org/

If you are referring to some other issue, then I'd need more details.

-Saravana

  reply	other threads:[~2022-05-13 17:26 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-29 22:09 [PATCH v1] driver core: Extend deferred probe timeout on driver registration Saravana Kannan
2022-05-13 12:48 ` Mark Brown
2022-05-13 13:58 ` Rob Herring
2022-05-13 17:25   ` Saravana Kannan [this message]
2022-05-16 13:49     ` Rob Herring
2022-05-20 23:30 ` Nathan Chancellor
2022-05-20 23:49   ` Saravana Kannan
2022-05-21  0:04     ` Nathan Chancellor
2022-05-21  0:15       ` Saravana Kannan
2022-05-23 15:17         ` Nathan Chancellor
2022-05-23 20:04           ` Saravana Kannan
2022-05-23 22:14             ` Nathan Chancellor
2022-05-24  3:43               ` Saravana Kannan
2022-05-24 16:41                 ` Sebastian Andrzej Siewior
2022-05-24 17:46                   ` Saravana Kannan
2022-05-25  7:11                     ` Sebastian Andrzej Siewior
2022-05-25 19:49                       ` Saravana Kannan
2022-05-29  8:34                         ` Niklas Cassel
2022-05-30  4:59                           ` Saravana Kannan

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAGETcx8=ZX+Pb4ioMVb7LfuF9c3HNP8g1+WMqZR=Pq7-9=DUCA@mail.gmail.com' \
    --to=saravanak@google.com \
    --cc=broonie@kernel.org \
    --cc=corbet@lwn.net \
    --cc=geert@linux-m68k.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=iommu@lists.linux-foundation.org \
    --cc=kernel-team@android.com \
    --cc=khilman@kernel.org \
    --cc=linus.walleij@linaro.org \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-gpio@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pm@vger.kernel.org \
    --cc=paul.kocialkowski@bootlin.com \
    --cc=pavel@ucw.cz \
    --cc=rafael@kernel.org \
    --cc=rjw@rjwysocki.net \
    --cc=robh@kernel.org \
    --cc=treding@nvidia.com \
    --cc=ulf.hansson@linaro.org \
    --cc=will@kernel.org \
    --cc=yoshihiro.shimoda.uh@renesas.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).