From: Frans Klaver <fransklaver@gmail.com>
To: Stephen Boyd <sboyd@codeaurora.org>
Cc: Guenter Roeck <linux@roeck-us.net>,
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Subject: Re: [PATCH 01/44] kernel: Add support for poweroff handler call chain
Date: Thu, 18 Jun 2015 08:53:50 +0200 [thread overview]
Message-ID: <CAH6sp9P7rq2y_hiQPHKUP85CwnEmp87yC7Psh4=29h-pYnb_yw@mail.gmail.com> (raw)
In-Reply-To: <55821936.4040704@codeaurora.org>
On Thu, Jun 18, 2015 at 3:04 AM, Stephen Boyd <sboyd@codeaurora.org> wrote:
> On 10/06/2014 10:28 PM, Guenter Roeck wrote:
>> Various drivers implement architecture and/or device specific means to
>> remove power from the system. For the most part, those drivers set the
>> global variable pm_power_off to point to a function within the driver.
>>
>> This mechanism has a number of drawbacks. Typically only one scheme
>> to remove power is supported (at least if pm_power_off is used).
>> At least in theory there can be multiple means remove power, some of
>> which may be less desirable. For example, some mechanisms may only
>> power off the CPU or the CPU card, while another may power off the
>> entire system. Others may really just execute a restart sequence
>> or drop into the ROM monitor. Using pm_power_off can also be racy
>> if the function pointer is set from a driver built as module, as the
>> driver may be in the process of being unloaded when pm_power_off is
>> called. If there are multiple poweroff handlers in the system, removing
>> a module with such a handler may inadvertently reset the pointer to
>> pm_power_off to NULL, leaving the system with no means to remove power.
>>
>> Introduce a system poweroff handler call chain to solve the described
>> problems. This call chain is expected to be executed from the
>> architecture specific machine_power_off() function. Drivers providing
>> system poweroff functionality are expected to register with this call chain.
>> By using the priority field in the notifier block, callers can control
>> poweroff handler execution sequence and thus ensure that the poweroff
>> handler with the optimal capabilities to remove power for a given system
>> is called first.
>
> What happened to this series? I want to add shutdown support to my
> platform and I need to write a register on the PMIC in one driver to
> configure it for shutdown instead of restart and then write an MMIO
> register to tell the PMIC to actually do the shutdown in another driver.
> It seems that the notifier solves this case for me, albeit with the
> slight complication that I need to order the two with some priority.
I was wondering the same thing. I did find out that things kind of
stalled after Linus cast doubt on the chosen path [1]. I'm not sure
there's any consensus on what would be best to do instead.
Frans
[1] https://lkml.org/lkml/2014/11/6/641
next prev parent reply other threads:[~2015-06-18 6:53 UTC|newest]
Thread overview: 101+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-07 5:28 [PATCH 00/44] kernel: Add support for poweroff handler call chain Guenter Roeck
2014-10-07 5:28 ` [PATCH 01/44] " Guenter Roeck
2014-10-07 7:46 ` Philippe Rétornaz
2014-10-09 10:31 ` Pavel Machek
2014-10-09 15:38 ` Guenter Roeck
2014-10-09 11:31 ` Geert Uytterhoeven
2014-10-09 13:25 ` Guenter Roeck
2015-06-18 1:04 ` Stephen Boyd
2015-06-18 6:53 ` Frans Klaver [this message]
2015-06-18 11:54 ` Guenter Roeck
2015-06-18 12:14 ` Frans Klaver
2015-06-18 15:30 ` Guenter Roeck
2015-06-18 21:40 ` Stephen Boyd
2014-10-07 5:28 ` [PATCH 02/44] memory: emif: Use API function to determine poweroff capability Guenter Roeck
2014-10-07 5:28 ` [PATCH 03/44] hibernate: Call have_kernel_poweroff instead of checking pm_power_off Guenter Roeck
2014-10-07 23:41 ` Rafael J. Wysocki
2014-10-09 10:32 ` Pavel Machek
2014-10-09 13:24 ` Guenter Roeck
2014-10-07 5:28 ` [PATCH 04/44] m68k: Replace mach_power_off with pm_power_off Guenter Roeck
2014-10-07 8:29 ` Geert Uytterhoeven
2014-10-07 5:28 ` [PATCH 05/44] mfd: as3722: Drop reference to pm_power_off from devicetree bindings Guenter Roeck
2014-10-07 10:59 ` Mark Rutland
2014-10-07 16:21 ` Rob Landley
2014-10-07 16:31 ` Guenter Roeck
2014-10-07 16:59 ` David Daney
2014-10-07 17:10 ` Rob Landley
2014-10-07 16:58 ` Mark Rutland
2014-10-07 5:28 ` [PATCH 06/44] gpio-poweroff: " Guenter Roeck
2014-10-07 11:03 ` Mark Rutland
2014-10-07 15:50 ` Andrew Lunn
2014-10-07 5:28 ` [PATCH 07/44] qnap-poweroff: " Guenter Roeck
2014-10-07 11:02 ` Mark Rutland
2014-10-07 15:57 ` Guenter Roeck
2014-10-07 15:51 ` Andrew Lunn
2014-10-07 5:28 ` [PATCH 08/44] kernel: Move pm_power_off to common code Guenter Roeck
2014-10-07 8:32 ` Geert Uytterhoeven
2014-10-07 13:58 ` Richard Weinberger
2014-10-07 23:42 ` Rafael J. Wysocki
2014-10-08 7:25 ` Jesper Nilsson
2014-10-08 11:06 ` 回复: " Xuetao Guan
2014-10-09 10:28 ` Catalin Marinas
2014-10-09 10:35 ` Vineet Gupta
2014-10-09 10:38 ` Pavel Machek
2014-10-09 13:14 ` Guenter Roeck
2014-10-09 20:24 ` Pavel Machek
2014-10-10 16:53 ` Guenter Roeck
2014-10-14 4:29 ` Hirokazu TAKATA
2014-10-07 5:28 ` [PATCH 09/44] mfd: palmas: Register with kernel poweroff handler Guenter Roeck
2014-10-07 5:28 ` [PATCH 10/44] mfd: axp20x: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 11/44] mfd: retu: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 12/44] mfd: ab8500-sysctrl: " Guenter Roeck
2014-10-07 8:00 ` Lee Jones
2014-10-09 10:36 ` Catalin Marinas
2014-10-09 10:49 ` Lee Jones
2014-10-09 13:26 ` Guenter Roeck
2014-10-09 13:33 ` Lee Jones
2014-10-09 15:45 ` Guenter Roeck
2014-10-09 15:54 ` Guenter Roeck
2014-10-07 5:28 ` [PATCH 13/44] mfd: max8907: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 14/44] mfd: tps80031: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 15/44] mfd: dm355evm_msp: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 16/44] mfd: tps6586x: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 17/44] mfd: tps65910: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 18/44] mfd: twl4030-power: " Guenter Roeck
2014-10-07 7:52 ` Lee Jones
2014-10-07 5:28 ` [PATCH 19/44] ipmi: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 20/44] power/reset: restart-poweroff: " Guenter Roeck
2014-10-07 16:06 ` Andrew Lunn
2014-10-07 5:28 ` [PATCH 21/44] power/reset: gpio-poweroff: " Guenter Roeck
2014-10-07 16:00 ` Andrew Lunn
2014-10-07 5:28 ` [PATCH 22/44] power/reset: as3722-poweroff: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 23/44] power/reset: qnap-poweroff: " Guenter Roeck
2014-10-07 16:02 ` Andrew Lunn
2014-10-07 5:28 ` [PATCH 24/44] power/reset: msm-powroff: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 25/44] power/reset: vexpress-poweroff: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 26/44] x86: iris: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 27/44] x86: apm: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 28/44] x86: olpc: Register xo1 poweroff handler " Guenter Roeck
2014-10-07 5:28 ` [PATCH 29/44] staging: nvec: Register " Guenter Roeck
2014-10-07 16:23 ` Greg Kroah-Hartman
2014-10-07 5:28 ` [PATCH 30/44] acpi: Register poweroff handler " Guenter Roeck
2014-10-07 5:28 ` [PATCH 31/44] arm: Register " Guenter Roeck
2014-10-07 8:04 ` Nicolas Ferre
2014-10-07 5:28 ` [PATCH 32/44] arm64: psci: " Guenter Roeck
2014-10-09 10:41 ` Catalin Marinas
2014-10-07 5:28 ` [PATCH 33/44] avr32: atngw100: " Guenter Roeck
2014-11-01 10:16 ` Hans-Christian Egtvedt
2014-11-01 17:02 ` Guenter Roeck
2014-10-07 5:28 ` [PATCH 34/44] ia64: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 35/44] m68k: " Guenter Roeck
2014-10-07 9:19 ` Geert Uytterhoeven
2014-10-07 5:28 ` [PATCH 36/44] mips: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 37/44] sh: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 38/44] x86: lguest: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 39/44] x86: ce4100: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 40/44] x86: intel-mid: Drop registration of dummy poweroff handlers Guenter Roeck
2014-10-07 5:28 ` [PATCH 41/44] x86: pmc_atom: Register poweroff handler with kernel poweroff handler Guenter Roeck
2014-10-07 5:28 ` [PATCH 42/44] efi: " Guenter Roeck
2014-10-07 5:28 ` [PATCH 43/44] hwmon: (ab8500) Call kernel_power_off instead of pm_power_off Guenter Roeck
2014-10-07 5:28 ` [PATCH 44/44] kernel: Remove pm_power_off Guenter Roeck
2014-10-07 23:43 ` Rafael J. Wysocki
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