LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Saravana Kannan <saravanak@google.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>,
	kernel-team@android.com, linux-kernel@vger.kernel.org,
	Jisheng Zhang <Jisheng.Zhang@synaptics.com>,
	Kevin Hilman <khilman@baylibre.com>,
	John Stultz <john.stultz@linaro.org>,
	Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
	Marc Zyngier <maz@kernel.org>
Subject: [PATCH v1 0/5] Enable fw_devlink=on by default
Date: Thu, 17 Dec 2020 19:16:58 -0800
Message-ID: <20201218031703.3053753-1-saravanak@google.com> (raw)

As discussed in LPC 2020, cyclic dependencies in firmware that couldn't
be broken using logic was one of the last remaining reasons
fw_devlink=on couldn't be set by default.

This series changes fw_devlink so that when a cyclic dependency is found
in firmware, the links between those devices fallback to permissive mode
behavior. This way, the rest of the system still benefits from
fw_devlink, but the ambiguous cases fallback to permissive mode.

Setting fw_devlink=on by default brings a bunch of benefits (currently,
only for systems with device tree firmware):
* Significantly cuts down deferred probes.
* Device probe is effectively attempted in graph order.
* Makes it much easier to load drivers as modules without having to
  worry about functional dependencies between modules (depmod is still
  needed for symbol dependencies).

Greg/Rafael,

Can we get this pulled into 5.11-rc1 or -rc2 soon please? I expect to
see some issues due to device drivers that aren't following best
practices (they don't expose the device to driver core). Want to
identify those early on and try to have them fixed before 5.11 release.
See [1] for an example of such a case.

If we do end up have to revert anything, it'll just be Patch 5/5 (a one
liner).

Marc,

You had hit issues with fw_devlink=on before on some of your systems.
Want to give this a shot?

Jisheng,

Want to fix up one of those gpio drivers you were having problems with?

Thanks,
Saravana

[1] - https://lore.kernel.org/lkml/CAGETcx9PiX==mLxB9PO8Myyk6u2vhPVwTMsA5NkD-ywH5xhusw@mail.gmail.com/

Cc: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Cc: Marc Zyngier <maz@kernel.org>

Saravana Kannan (5):
  driver core: Add debug logs for device link related probe deferrals
  driver core: Add device link support for INFERRED flag
  driver core: Have fw_devlink use DL_FLAG_INFERRED
  driver core: Handle cycles in device links created by fw_devlink
  driver core: Set fw_devlink=on by default

 drivers/base/core.c    | 101 +++++++++++++++++++++++++++++++++++------
 include/linux/device.h |   2 +
 2 files changed, 90 insertions(+), 13 deletions(-)

-- 
2.29.2.684.gfbc64c5ab5-goog


             reply index

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-18  3:16 Saravana Kannan [this message]
2020-12-18  3:16 ` [PATCH v1 1/5] driver core: Add debug logs for device link related probe deferrals Saravana Kannan
2020-12-18  3:17 ` [PATCH v1 2/5] driver core: Add device link support for INFERRED flag Saravana Kannan
2020-12-18  3:17 ` [PATCH v1 3/5] driver core: Have fw_devlink use DL_FLAG_INFERRED Saravana Kannan
2020-12-18  3:17 ` [PATCH v1 4/5] driver core: Handle cycles in device links created by fw_devlink Saravana Kannan
2020-12-18  6:39   ` kernel test robot
2020-12-18  6:39   ` [RFC PATCH] driver core: fw_devlink_relax_cycle() can be static kernel test robot
2020-12-18  6:48   ` [PATCH v1 4/5] driver core: Handle cycles in device links created by fw_devlink kernel test robot
2020-12-18  7:12   ` kernel test robot
2020-12-18  3:17 ` [PATCH v1 5/5] driver core: Set fw_devlink=on by default Saravana Kannan
     [not found]   ` <CGME20210111111245eucas1p15acde7ecc2ca7f7782beb8ed74c72022@eucas1p1.samsung.com>
2021-01-11 11:12     ` Marek Szyprowski
     [not found]       ` <CGME20210111141814eucas1p1f388df07b789693a999042b27f0d8c2a@eucas1p1.samsung.com>
2021-01-11 14:18         ` Marek Szyprowski
2021-01-11 21:47           ` Saravana Kannan
2021-01-12  7:11             ` Marek Szyprowski
2021-01-12 20:51               ` Saravana Kannan
2021-01-13  7:04                 ` Marek Szyprowski
2021-01-13 19:23                   ` Saravana Kannan
2021-01-14  7:36                     ` Marek Szyprowski
2021-01-14 18:08                       ` Saravana Kannan
2021-01-18 17:43                 ` Geert Uytterhoeven
2021-01-17 23:01   ` Michael Walle
2021-01-18 21:01     ` Saravana Kannan
2021-01-19 10:41       ` Michael Walle
2021-01-20  0:00         ` Saravana Kannan
2021-01-18 17:39   ` Geert Uytterhoeven
2021-01-18 17:59     ` Marc Zyngier
2021-01-18 19:16       ` Geert Uytterhoeven
2021-01-18 19:30         ` Marc Zyngier
2021-01-18 21:18         ` Saravana Kannan
2021-01-19  9:05           ` Geert Uytterhoeven
2021-01-19 18:08             ` Saravana Kannan
2021-01-19 21:50               ` Saravana Kannan
2021-01-20  9:40                 ` Geert Uytterhoeven
2021-01-20 14:26                   ` Geert Uytterhoeven
2021-01-20 17:22                     ` Saravana Kannan
2021-01-21 16:04                       ` Geert Uytterhoeven
2021-01-25 23:30                         ` Saravana Kannan
2021-01-26  8:25                           ` Geert Uytterhoeven
2021-01-20  9:11               ` Geert Uytterhoeven
2021-01-21  8:22   ` [TEST PATCH v1] driver: core: Make fw_devlink=on more forgiving Saravana Kannan
2021-01-21  8:27     ` Saravana Kannan
2021-01-21 10:37       ` Geert Uytterhoeven
2021-01-22  1:07         ` Saravana Kannan
2021-01-21 10:33     ` Marek Szyprowski
2021-01-25 17:05   ` [PATCH v1 5/5] driver core: Set fw_devlink=on by default Tudor.Ambarus
2021-01-25 18:16     ` Saravana Kannan
2021-01-28 10:59       ` Tudor.Ambarus
2021-01-28 17:04         ` Saravana Kannan
2021-02-10  5:54   ` Guenter Roeck
2021-02-10  8:20     ` Saravana Kannan
2021-02-10 15:10       ` Guenter Roeck
2021-02-10 20:52         ` Saravana Kannan
2021-02-10 21:21           ` Guenter Roeck
2021-02-17  2:39             ` Saravana Kannan
2021-02-17  3:05               ` Guenter Roeck
2021-02-17  3:13                 ` Saravana Kannan
2020-12-18 21:11 ` [PATCH v1 0/5] Enable " Saravana Kannan
2020-12-21  8:18 ` Jisheng Zhang
     [not found]   ` <CAHp75VfqL1QuvjCZ7p23e_2qhY3DUgVNaS--Uk1mEoEHsD8GBA@mail.gmail.com>
2021-01-14 16:49     ` Saravana Kannan
2020-12-21  9:48 ` Rafael J. Wysocki
2021-01-07 20:05 ` Greg Kroah-Hartman
2021-01-07 21:53   ` Saravana Kannan
2021-01-13 11:11   ` Marc Zyngier
2021-01-13 15:27     ` Jon Hunter
2021-01-13 21:29       ` Saravana Kannan
2021-01-14 11:34         ` Jon Hunter
2021-01-14 16:40           ` Saravana Kannan
2021-01-14 16:47             ` Jon Hunter
2021-01-14 16:52               ` Saravana Kannan
2021-01-14 18:55                 ` Jon Hunter
2021-01-14 21:50                   ` Saravana Kannan
2021-01-15 16:12                     ` Jon Hunter
2021-01-15 17:44                       ` Saravana Kannan
2021-01-13 20:56     ` Saravana Kannan
2021-01-13 11:30 ` Jon Hunter
2021-01-13 21:26   ` Saravana Kannan
2021-01-14 16:11     ` Jon Hunter
2021-01-14 16:47       ` Saravana Kannan
2021-01-14 16:56         ` Jon Hunter
2021-01-28 15:03           ` Jon Hunter
2021-01-28 17:27             ` Saravana Kannan
2021-02-11  0:02             ` Saravana Kannan
2021-02-11 15:03               ` Rafael J. Wysocki
2021-02-11 17:14                 ` Saravana Kannan
2021-02-11 17:48                   ` Rafael J. Wysocki
2021-02-12  3:04                     ` Saravana Kannan
2021-01-13 11:44 ` Nicolas Saenz Julienne
2021-01-13 11:48   ` Marc Zyngier
2021-01-13 21:27     ` 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=20201218031703.3053753-1-saravanak@google.com \
    --to=saravanak@google.com \
    --cc=Jisheng.Zhang@synaptics.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=john.stultz@linaro.org \
    --cc=kernel-team@android.com \
    --cc=khilman@baylibre.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=maz@kernel.org \
    --cc=nsaenzjulienne@suse.de \
    --cc=rafael@kernel.org \
    /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

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git