linux-kernel - Re: [PATCH v1] ACPI: battery: Reduce unnecessary calls to acpi_battery

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Message-ID: <74beaec6-eae5-4456-9202-f77c71456682@kylinos.cn>
Date: Fri, 16 May 2025 13:13:31 +0800
From: zhangzihuan <zhangzihuan@...inos.cn>
To: "Rafael J. Wysocki" <rafael@...nel.org>
Cc: lenb@...nel.org, linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] ACPI: battery: Reduce unnecessary calls to
 acpi_battery_update()

Hi Rafael,
Thank you for the review!

在 2025/5/10 02:23, Rafael J. Wysocki 写道:
> On Tue, Apr 22, 2025 at 11:11 AM zhangzihuan <zhangzihuan@...inos.cn> wrote:
>> When entering the acpi_mattery_notify function, no matter what the event
>> is, acpi_mattery_update will definitely be called.
> I think you mean acpi_battery_update().
Right.
>> Use the acpi_listen command to listen, sometimes the log looks like this:
>>
>> battery xxx:00 00000081 00000001
>> battery xxx:00 00000000 00000001
>> battery xxx:00 00000080 00000001
>>
>> Firmware manufacturers will customize some events like 0x0, so
>> non-matching events will be ignored.
> I don't quite get what you are trying to achieve here.
>
While the laptop is charging, acpi_battery_notify() receives a steady 
stream of 0x81 events, and only receives 0x80 events
when the battery is almost fully charged or the adapter is plugged in. 
If acpi_battery_update() is just to
update the battery status,  it didn't need to be called frequently.
>> Signed-off-by: zhangzihuan <zhangzihuan@...inos.cn>
>> ---
>>   drivers/acpi/battery.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
>> index 6760330a8af5..9446c57b77e7 100644
>> --- a/drivers/acpi/battery.c
>> +++ b/drivers/acpi/battery.c
>> @@ -1083,7 +1083,8 @@ static void acpi_battery_notify(acpi_handle handle, u32 event, void *data)
>>                  msleep(battery_notification_delay_ms);
>>          if (event == ACPI_BATTERY_NOTIFY_INFO)
>>                  acpi_battery_refresh(battery);
>> -       acpi_battery_update(battery, false);
>> +       if (event == ACPI_BATTERY_NOTIFY_STATUS)
>> +               acpi_battery_update(battery, false);
> So only call acpi_battery_update() for ACPI_BATTERY_NOTIFY_STATUS.
>
> Why do you think this is the only case in which acpi_battery_update()
> needs to be called?
acpi_battery_update() calls acpi_battery_get_status() to get the battery 
update status. It will only be updated
if it receives an event that the battery status has changed.
>>          acpi_bus_generate_netlink_event(device->pnp.device_class,
>>                                          dev_name(&device->dev), event,
>>                                          acpi_battery_present(battery));
>> --