From: Armin Wolf <W_Armin@gmx.de>
To: "Rafael J. Wysocki" <rafael@kernel.org>,
Hans de Goede <hdegoede@redhat.com>
Cc: Mark Gross <markgross@kernel.org>, Len Brown <lenb@kernel.org>,
Henrique de Moraes Holschuh <hmh@hmh.eng.br>,
Matan Ziv-Av <matan@svgalib.org>,
Corentin Chary <corentin.chary@gmail.com>,
Jeremy Soller <jeremy@system76.com>,
productdev@system76.com,
Platform Driver <platform-driver-x86@vger.kernel.org>,
ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/5] ACPI: battery: Do not unload battery hooks on single error
Date: Mon, 19 Sep 2022 22:35:33 +0200 [thread overview]
Message-ID: <f0b17ba6-3d3c-cbc1-ec0d-ec59c73f06f6@gmx.de> (raw)
In-Reply-To: <f2af5d01-a2cd-ae96-24c7-d61f5f0d0bc3@gmx.de>
Am 19.09.22 um 21:12 schrieb Armin Wolf:
> Am 19.09.22 um 18:27 schrieb Rafael J. Wysocki:
>
>> On Mon, Sep 19, 2022 at 12:42 PM Hans de Goede <hdegoede@redhat.com>
>> wrote:
>>> Hi,
>>>
>>> On 9/12/22 13:53, Armin Wolf wrote:
>>>> Currently, battery hooks are being unloaded if they return
>>>> an error when adding a single battery.
>>>> This however also causes the removal of successfully added
>>>> hooks if they return -ENODEV for a single unsupported
>>>> battery.
>>>>
>>>> Do not unload battery hooks in such cases since the hook
>>>> handles any cleanup actions.
>>>>
>>>> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
>>> Maybe instead of removing all error checking, allow -ENODEV
>>> and behave as before when the error is not -ENODEV ?
>>>
>>> Otherwise we should probably make the add / remove callbacks
>>> void to indicate that any errors are ignored.
>>>
>>> Rafael, do you have any opinion on this?
>> IMV this is not a completely safe change, because things may simply
>> not work in the cases in which an error is returned.
>>
>> It would be somewhat better to use a special error code to indicate
>> "no support" (eg. -ENOTSUPP) and ignore that one only.
>
> I would favor -ENODEV then, since it is already used by quiet a few
> drivers
> to indicate a unsupported battery.
>
> Armin Wolf
>
While checking all instances where the battery hook mechanism is currently used,
i found out that all but a single battery hook return -ENODEV for all errors they
encounter, the exception being the huawei-wmi driver.
I do not know the reason for this, but i fear unloading the extension on for
example -ENOTSUP will result in similar behavior by hooks wanting to avoid being
unloaded on harmless errors.
However, i agree that when ignoring all errors, battery extensions which provide
similar attributes may currently delete each others attributes.
Any idea on how to solve this?
Armin Wolf
>>>> ---
>>>> drivers/acpi/battery.c | 24 +++---------------------
>>>> 1 file changed, 3 insertions(+), 21 deletions(-)
>>>>
>>>> diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
>>>> index 306513fec1e1..e59c261c7c59 100644
>>>> --- a/drivers/acpi/battery.c
>>>> +++ b/drivers/acpi/battery.c
>>>> @@ -724,20 +724,10 @@ void battery_hook_register(struct
>>>> acpi_battery_hook *hook)
>>>> * its attributes.
>>>> */
>>>> list_for_each_entry(battery, &acpi_battery_list, list) {
>>>> - if (hook->add_battery(battery->bat)) {
>>>> - /*
>>>> - * If a add-battery returns non-zero,
>>>> - * the registration of the extension has failed,
>>>> - * and we will not add it to the list of loaded
>>>> - * hooks.
>>>> - */
>>>> - pr_err("extension failed to load: %s",
>>>> hook->name);
>>>> - __battery_hook_unregister(hook, 0);
>>>> - goto end;
>>>> - }
>>>> + hook->add_battery(battery->bat);
>>>> }
>>>> pr_info("new extension: %s\n", hook->name);
>>>> -end:
>>>> +
>>>> mutex_unlock(&hook_mutex);
>>>> }
>>>> EXPORT_SYMBOL_GPL(battery_hook_register);
>>>> @@ -762,15 +752,7 @@ static void battery_hook_add_battery(struct
>>>> acpi_battery *battery)
>>>> * during the battery module initialization.
>>>> */
>>>> list_for_each_entry_safe(hook_node, tmp, &battery_hook_list,
>>>> list) {
>>>> - if (hook_node->add_battery(battery->bat)) {
>>>> - /*
>>>> - * The notification of the extensions has
>>>> failed, to
>>>> - * prevent further errors we will unload the
>>>> extension.
>>>> - */
>>>> - pr_err("error in extension, unloading: %s",
>>>> - hook_node->name);
>>>> - __battery_hook_unregister(hook_node, 0);
>>>> - }
>>>> + hook_node->add_battery(battery->bat);
>>>> }
>>>> mutex_unlock(&hook_mutex);
>>>> }
>>>> --
>>>> 2.30.2
>>>>
next prev parent reply other threads:[~2022-09-19 20:36 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-12 12:53 [PATCH 0/5] platform/x86: dell: Add new dell-wmi-ddv driver Armin Wolf
2022-09-12 12:53 ` [PATCH 1/5] ACPI: battery: Do not unload battery hooks on single error Armin Wolf
2022-09-19 10:42 ` Hans de Goede
2022-09-19 16:27 ` Rafael J. Wysocki
2022-09-19 19:12 ` Armin Wolf
2022-09-19 20:35 ` Armin Wolf [this message]
2022-09-27 14:29 ` Hans de Goede
2022-09-27 15:44 ` Armin Wolf
2022-09-12 12:53 ` [PATCH 2/5] ACPI: battery: Simplify battery_hook_unregister() Armin Wolf
2022-09-19 10:42 ` Hans de Goede
2022-09-12 12:53 ` [PATCH 3/5] ACPI: battery: Allow battery hooks to be registered multiple times Armin Wolf
2022-09-12 16:42 ` Barnabás Pőcze
2022-09-12 17:29 ` Armin Wolf
2022-09-19 11:18 ` Hans de Goede
2022-09-19 17:42 ` Barnabás Pőcze
2022-09-12 12:53 ` [PATCH 4/5] ACPI: battery: Allow for passing data to battery hooks Armin Wolf
2022-09-19 11:08 ` Hans de Goede
2022-09-12 12:53 ` [PATCH 5/5] platform/x86: dell: Add new dell-wmi-ddv driver Armin Wolf
2022-09-12 21:56 ` Randy Dunlap
2022-09-13 14:40 ` Armin Wolf
2022-09-13 16:08 ` Limonciello, Mario
2022-09-13 16:45 ` Armin Wolf
2022-09-13 18:27 ` Randy Dunlap
2022-09-13 18:30 ` Limonciello, Mario
2022-09-13 18:37 ` Randy Dunlap
2022-09-19 11:33 ` Hans de Goede
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