Linux-ACPI Archive on lore.kernel.org
 help / color / Atom feed
From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: Andrzej Pietrasiewicz <andrzej.p@collabora.com>,
	linux-pm@vger.kernel.org
Cc: Zhang Rui <rui.zhang@intel.com>,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Len Brown <lenb@kernel.org>, Jiri Pirko <jiri@mellanox.com>,
	Ido Schimmel <idosch@mellanox.com>,
	"David S . Miller" <davem@davemloft.net>,
	Peter Kaestle <peter@piie.net>,
	Darren Hart <dvhart@infradead.org>,
	Andy Shevchenko <andy@infradead.org>,
	Support Opensource <support.opensource@diasemi.com>,
	Amit Kucheria <amit.kucheria@verdurent.com>,
	Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>,
	NXP Linux Team <linux-imx@nxp.com>,
	Allison Randal <allison@lohutok.net>,
	Enrico Weigelt <info@metux.net>,
	Gayatri Kammela <gayatri.kammela@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-acpi@vger.kernel.org, netdev@vger.kernel.org,
	platform-driver-x86@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, kernel@collabora.com,
	Barlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Subject: Re: [RFC v3 1/2] thermal: core: Let thermal zone device's mode be stored in its struct
Date: Sat, 23 May 2020 23:24:51 +0200
Message-ID: <f39c5ca6-5efa-889c-21f5-632dfd24715e@linaro.org> (raw)
In-Reply-To: <20200417162020.19980-2-andrzej.p@collabora.com>

Hi Andrzej,

On 17/04/2020 18:20, Andrzej Pietrasiewicz wrote:
> Thermal zone devices' mode is stored in individual drivers. This patch
> changes it so that mode is stored in struct thermal_zone_device instead.
> 
> As a result all driver-specific variables storing the mode are not needed
> and are removed. Consequently, the get_mode() implementations have nothing
> to operate on and need to be removed, too.
> 
> Some thermal framework specific functions are introduced:
> 
> thermal_zone_device_get_mode()
> thermal_zone_device_set_mode()
> thermal_zone_device_enable()
> thermal_zone_device_disable()
> 
> thermal_zone_device_get_mode() and its "set" counterpart take tzd's lock
> and the "set" calls driver's set_mode() if provided, so the latter must
> not take this lock again. At the end of the "set"
> thermal_zone_device_update() is called so drivers don't need to repeat this
> invocation in their specific set_mode() implementations.
> 
> The scope of the above 4 functions is purposedly limited to the thermal
> framework and drivers are not supposed to call them. This encapsulation
> does not fully work at the moment for some drivers, though:
> 
> - platform/x86/acerhdf.c
> - drivers/thermal/imx_thermal.c
> - drivers/thermal/intel/intel_quark_dts_thermal.c
> - drivers/thermal/of-thermal.c
> 
> and they manipulate struct thermal_zone_device's members directly.
> 
> struct thermal_zone_params gains a new member called initial_mode, which
> is used to set tzd's mode at registration time.
> 
> The sysfs "mode" attribute is always exposed from now on, because all
> thermal zone devices now have their get_mode() implemented at the generic
> level and it is always available. Exposing "mode" doesn't hurt the drivers
> which don't provide their own set_mode(), because writing to "mode" will
> result in -EPERM, as expected.

The result is great, that is a nice cleanup of the thermal framework.

After review it appears there are still problems IMO, especially with
the suspend / resume path. The patch is big, it is a bit complex to
comment. I suggest to re-org the changes as following:

 - patch 1 : Add the four functions:

 * thermal_zone_device_set_mode()
 * thermal_zone_device_enable()
 * thermal_zone_device_disable()
 * thermal_zone_device_is_enabled()

*but* do not export thermal_zone_device_set_mode(), it must stay private
to the thermal framework ATM.

 - patch 2 : Add the mode THERMAL_DEVICE_SUSPENDED

In the thermal_pm_notify() in the:

 - PM_SUSPEND_PREPARE case, set the mode to THERMAL_DEVICE_SUSPENDED if
the mode is THERMAL_DEVICE_ENABLED

 - PM_POST_SUSPEND case, set the mode to THERMAL_DEVICE_ENABLED, if the
mode is THERMAL_DEVICE_SUSPENDED

 - patch 3 : Change the monitor function

Change monitor_thermal_zone() function to set the polling to zero if the
mode is THERMAL_DEVICE_DISABLED

 - patch 4 : Do the changes to remove get_mode() ops

Make sure there is no access to tz->mode from the drivers anymore but
use of the functions of patch 1. IMO, this is the tricky part because a
part of the drivers are not calling the update after setting the mode
while the function thermal_zone_device_enable()/disable() call update
via the thermal_zone_device_set_mode(), so we must be sure to not break
anything.

 - patch 5 : Do the changes to remove set_mode() ops users

As the patch 3 sets the polling to zero, the routine in the driver
setting the polling to zero is no longer needed (eg. in the mellanox
driver). I expect int300 to be the last user of this ops, hopefully we
can find a way to get rid of the specific call done inside and then
remove the ops.

The initial_mode approach looks hackish, I suggest to make the default
the thermal zone disabled after creating and then explicitly enable it.
Note that is what do a lot of drivers already.

Hopefully, these changes are git-bisect safe.

Does it make sense ?












-- 
<http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs

Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog

  parent reply index

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-07 17:49 [RFC 0/8] Stop monitoring disabled devices Andrzej Pietrasiewicz
2020-04-07 17:49 ` [RFC 1/8] thermal: int3400_thermal: Statically initialize .get_mode()/.set_mode() ops Andrzej Pietrasiewicz
     [not found]   ` <CGME20200415091204eucas1p1983548c2db52d8d0c2a5367034ec80dd@eucas1p1.samsung.com>
2020-04-15  9:12     ` Bartlomiej Zolnierkiewicz
2020-04-07 17:49 ` [RFC 2/8] thermal: Properly handle mode values in .set_mode() Andrzej Pietrasiewicz
     [not found]   ` <CGME20200415100543eucas1p24e24293da39844ca8791db86af5365a7@eucas1p2.samsung.com>
2020-04-15 10:05     ` Bartlomiej Zolnierkiewicz
2020-04-07 17:49 ` [RFC 3/8] thermal: Store thermal mode in a dedicated enum Andrzej Pietrasiewicz
     [not found]   ` <CGME20200415100944eucas1p1dcfeb784e790ca2fc3417fd2797e3f5d@eucas1p1.samsung.com>
2020-04-15 10:09     ` Bartlomiej Zolnierkiewicz
2020-04-07 17:49 ` [RFC 4/8] thermal: core: Introduce THERMAL_DEVICE_INITIAL Andrzej Pietrasiewicz
2020-04-07 17:49 ` [RFC 5/8] thermal: core: Monitor thermal zone after mode change Andrzej Pietrasiewicz
2020-04-07 17:49 ` [RFC 6/8] thermal: Set initial state to THERMAL_DEVICE_INITIAL Andrzej Pietrasiewicz
2020-04-07 17:49 ` [RFC 7/8] thermal: of: Monitor thermal zone after enabling it Andrzej Pietrasiewicz
     [not found]   ` <CGME20200415101829eucas1p18e21324d3c39926fffc6c8b5dc52f206@eucas1p1.samsung.com>
2020-04-15 10:18     ` Bartlomiej Zolnierkiewicz
2020-04-07 17:49 ` [RFC 8/8] thermal: Stop polling DISABLED thermal devices Andrzej Pietrasiewicz
2020-04-09 10:29 ` [RFC 0/8] Stop monitoring disabled devices Daniel Lezcano
2020-04-09 11:10   ` Andrzej Pietrasiewicz
     [not found]     ` <CGME20200415104010eucas1p101278e53e34a2e56dfc7c82b533a9122@eucas1p1.samsung.com>
2020-04-15 10:40       ` Bartlomiej Zolnierkiewicz
2020-04-17 16:23         ` Andrzej Pietrasiewicz
2020-04-19 11:42           ` Bartlomiej Zolnierkiewicz
2020-04-17 21:11         ` Peter Kästle
2020-04-14 18:00   ` [RFC v2 0/9] " Andrzej Pietrasiewicz
2020-04-14 18:00     ` [RFC v2 1/9] thermal: int3400_thermal: Statically initialize .get_mode()/.set_mode() ops Andrzej Pietrasiewicz
2020-04-15  9:23       ` Daniel Lezcano
2020-04-14 18:00     ` [RFC v2 2/9] thermal: Eliminate an always-false condition Andrzej Pietrasiewicz
2020-04-14 18:00     ` [RFC v2 3/9] thermal: Properly handle mode values in .set_mode() Andrzej Pietrasiewicz
2020-04-14 22:14       ` Daniel Lezcano
2020-04-14 18:01     ` [RFC v2 4/9] thermal: core: Let thermal zone device's mode be stored in its struct Andrzej Pietrasiewicz
2020-04-14 22:30       ` Daniel Lezcano
2020-04-14 18:01     ` [RFC v2 5/9] thermal: Store mode in thermal_zone_device Andrzej Pietrasiewicz
2020-04-15 10:55       ` Daniel Lezcano
2020-04-17 16:20         ` [RFC v3 0/2] Stop monitoring disabled devices Andrzej Pietrasiewicz
2020-04-17 16:20           ` [RFC v3 1/2] thermal: core: Let thermal zone device's mode be stored in its struct Andrzej Pietrasiewicz
2020-04-17 20:44             ` Andy Shevchenko
2020-04-19 11:38             ` Bartlomiej Zolnierkiewicz
2020-04-19 13:10               ` Bartlomiej Zolnierkiewicz
2020-04-20 18:17                 ` [PATCH 0/2] Stop monitoring disabled devices Andrzej Pietrasiewicz
2020-04-20 18:17                   ` [PATCH 1/2] thermal: core: Let thermal zone device's mode be stored in its struct Andrzej Pietrasiewicz
2020-04-20 18:17                   ` [PATCH 2/2] thermal: core: Stop polling DISABLED thermal devices Andrzej Pietrasiewicz
2020-04-22 16:12                   ` [PATCH RESEND 1/2] thermal: core: Let thermal zone device's mode be stored in its struct Andrzej Pietrasiewicz
2020-04-23 14:39                     ` Bartlomiej Zolnierkiewicz
2020-04-23 16:57                       ` [PATCH v3 0/2] Stop monitoring disabled devices Andrzej Pietrasiewicz
2020-04-23 16:57                         ` [PATCH v3 1/2] thermal: core: Let thermal zone device's mode be stored in its struct Andrzej Pietrasiewicz
2020-05-04  7:00                           ` Bartlomiej Zolnierkiewicz
2020-04-23 16:57                         ` [PATCH v3 2/2] thermal: core: Stop polling DISABLED thermal devices Andrzej Pietrasiewicz
2020-04-24  9:03                           ` Zhang, Rui
2020-04-27 14:20                             ` Zhang, Rui
2020-04-27 18:34                               ` Andrzej Pietrasiewicz
2020-04-28 13:55                                 ` Zhang, Rui
2020-04-20 11:03               ` [RFC v3 1/2] thermal: core: Let thermal zone device's mode be stored in its struct Andrzej Pietrasiewicz
2020-04-20 18:19                 ` Andrzej Pietrasiewicz
2020-05-23 21:24             ` Daniel Lezcano [this message]
2020-05-25 19:35               ` Andrzej Pietrasiewicz
2020-05-25 22:08                 ` Daniel Lezcano
2020-05-26 16:56                   ` Andrzej Pietrasiewicz
2020-04-17 16:20           ` [RFC v3 2/2] thermal: core: Stop polling DISABLED thermal devices Andrzej Pietrasiewicz
2020-04-19 13:50           ` [RFC v3 1/2] thermal: core: Let thermal zone device's mode be stored in its struct Peter Kästle
2020-04-14 18:01     ` [RFC v2 6/9] thermal: Remove get_mode() method Andrzej Pietrasiewicz
2020-04-14 18:01     ` [RFC v2 7/9] thermal: core: Monitor thermal zone after mode change Andrzej Pietrasiewicz
2020-04-14 18:01     ` [RFC v2 8/9] thermal: of: Monitor thermal zone after enabling it Andrzej Pietrasiewicz
2020-04-14 18:01     ` [RFC v2 9/9] thermal: core: Stop polling DISABLED thermal devices Andrzej Pietrasiewicz
2020-04-14 21:52     ` [RFC v2 0/9] Stop monitoring disabled devices Ezequiel Garcia

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=f39c5ca6-5efa-889c-21f5-632dfd24715e@linaro.org \
    --to=daniel.lezcano@linaro.org \
    --cc=allison@lohutok.net \
    --cc=amit.kucheria@verdurent.com \
    --cc=andrzej.p@collabora.com \
    --cc=andy@infradead.org \
    --cc=b.zolnierkie@samsung.com \
    --cc=davem@davemloft.net \
    --cc=dvhart@infradead.org \
    --cc=festevam@gmail.com \
    --cc=gayatri.kammela@intel.com \
    --cc=idosch@mellanox.com \
    --cc=info@metux.net \
    --cc=jiri@mellanox.com \
    --cc=kernel@collabora.com \
    --cc=kernel@pengutronix.de \
    --cc=lenb@kernel.org \
    --cc=linux-acpi@vger.kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-imx@nxp.com \
    --cc=linux-pm@vger.kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=peter@piie.net \
    --cc=platform-driver-x86@vger.kernel.org \
    --cc=rjw@rjwysocki.net \
    --cc=rui.zhang@intel.com \
    --cc=s.hauer@pengutronix.de \
    --cc=shawnguo@kernel.org \
    --cc=support.opensource@diasemi.com \
    --cc=tglx@linutronix.de \
    /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

Linux-ACPI Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-acpi/0 linux-acpi/git/0.git

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

Example config snippet for mirrors

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


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