linux-kernel - Re: [PATCH 0/4] power: supply: add charge_behaviour property (force-discharge, inhibit-charge)

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Message-ID: <015913c3-171f-3ecb-2813-54404d6db273@redhat.com>
Date:   Sat, 4 Dec 2021 14:56:00 +0100
From:   Hans de Goede <hdegoede@...hat.com>
To:     Sebastian Reichel <sebastian.reichel@...labora.com>,
        Thomas Weißschuh <linux@...ssschuh.net>
Cc:     linux-pm@...r.kernel.org, ibm-acpi-devel@...ts.sourceforge.net,
        platform-driver-x86@...r.kernel.org,
        Mark Gross <markgross@...nel.org>,
        Henrique de Moraes Holschuh <hmh@....eng.br>,
        linux-kernel@...r.kernel.org, linrunner@....net, bberg@...hat.com,
        hadess@...ess.net, markpearson@...ovo.com,
        nicolopiazzalunga@...il.com, njoshi1@...ovo.com, smclt30p@...il.com
Subject: Re: [PATCH 0/4] power: supply: add charge_behaviour property
 (force-discharge, inhibit-charge)

Hi,

On 12/3/21 22:33, Sebastian Reichel wrote:
> Hi,
> 
> On Wed, Nov 24, 2021 at 12:27:00AM +0100, Thomas Weißschuh wrote:
>> This series adds support for the charge_behaviour property to the power
>> subsystem and thinkpad_acpi driver.
>>
>> As thinkpad_acpi has to use the 'struct power_supply' created by the generic
>> ACPI driver it has to rely on custom sysfs attributes instead of proper
>> power_supply properties to implement this property.
>>
>> Patch 1: Adds the power_supply documentation and basic public API
>> Patch 2: Adds helpers to power_supply core to help drivers implement the
>>   charge_behaviour attribute
>> Patch 3: Adds support for force-discharge to thinkpad_acpi.
>> Patch 4: Adds support for inhibit-discharge to thinkpad_acpi.
>>
>> Patch 3 and 4 are largely taken from other patches and adapted to the new API.
>> (Links are in the patch trailer)
>>
>> Ognjen Galic:
>>
>> Your S-o-b is on the original inhibit_charge and force_discharge patches.
>> I would like to add you as Co-developed-by but to do that it will also require
>> your S-o-b. Could you give your sign-offs for the new patches, so you can be
>> properly attributed?
>>
>> Sebastian Reichel:
>>
>> Currently the series does not actually support the property as a proper
>> powersupply property handled fully by power_supply_sysfs.c because there would
>> be no user for this property.
> 
> I'm not too happy how the acpi-battery hooks work, but that's not
> your fault and this patchset does not really make the situation
> worse. So:
> 
> Acked-by: Sebastian Reichel <sebastian.reichel@...labora.com>

I haven't looked at the thinkpad_apci.c bits closely yet (for this new version),
but assuming those are ready for merging too, we need to discuss about how
to merge this.

The thinkpad_acpi code has already seen quite a lot of changes in -next,
so I would like the thinkpad_acpi changes to go upstream through the
platform-drivers-x86.git tree to avoid conflicts.

As such I think it is best if you (Sebastian) can prepare an immutable
branch with patch 1 + 2 for me to merge. Then even if patch 3 + 4 need
more work, Thomas can just respin those on top of the immutable branch.

Alternatively I can take the entire series upstream through the
platform-drivers-x86.git tree if that is ok with you (Sebastian).

Either way please let me know how you want to proceed with this.

Regards,

Hans



>> Previous discussions about the API:
>>
>> https://lore.kernel.org/platform-driver-x86/20211108192852.357473-1-linux@weissschuh.net/
>> https://lore.kernel.org/platform-driver-x86/21569a89-8303-8573-05fb-c2fec29983d1@gmail.com/
>>
>> v1: https://lore.kernel.org/lkml/20211113104225.141333-1-linux@weissschuh.net/
>> v1 -> v2:
>>
>> * Use sysfs_emit-APIs instead of plain sprintf
>> * More cecks for actual feature availability
>> * Validation of the written values
>> * Read inhibit-charge via BICG instead of PSSG (peak shift state)
>> * Don't mangle error numbers in charge_behaviour_store()
>>
>> Open points:
>>
>> Thomas Koch has observed that on a T450s with two batteries
>> inhibit-charge on BAT0 will affect both batteries and for BAT1 it is ignored
>> entirely, this seems to be a bug in the EC.
>> On my T460s with two batteries it works correctly.
>>
>> Thomas Weißschuh (4):
>>   power: supply: add charge_behaviour attributes
>>   power: supply: add helpers for charge_behaviour sysfs
>>   platform/x86: thinkpad_acpi: support force-discharge
>>   platform/x86: thinkpad_acpi: support inhibit-charge
>>
>>  Documentation/ABI/testing/sysfs-class-power |  14 ++
>>  drivers/platform/x86/thinkpad_acpi.c        | 191 +++++++++++++++++++-
>>  drivers/power/supply/power_supply_sysfs.c   |  51 ++++++
>>  include/linux/power_supply.h                |  16 ++
>>  4 files changed, 268 insertions(+), 4 deletions(-)
>>
>>
>> base-commit: 66f4beaa6c1d28161f534471484b2daa2de1dce0
>> -- 
>> 2.34.0
>>