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SubjectRe: [PATCH] ACPI/Battery: Retry to get Battery information if failed during probing
On 2014年06月16日 10:35, Zheng, Lv wrote:
> Hi,
>
>> From: linux-acpi-owner@vger.kernel.org [mailto:linux-acpi-owner@vger.kernel.org] On Behalf Of Lan Tianyu
>> Sent: Monday, June 16, 2014 10:12 AM
>> To: David Rientjes
>> Cc: rjw@rjwysocki.net; lenb@kernel.org; naszar@ya.ru; linux-acpi@vger.kernel.org; linux-kernel@vger.kernel.org
>> Subject: Re: [PATCH] ACPI/Battery: Retry to get Battery information if failed during probing
>>
>> On 2014年06月14日 05:46, David Rientjes wrote:
>>> On Fri, 13 Jun 2014, Lan Tianyu wrote:
>>>
>>>> How about this?
>>>>
>>>> - result = acpi_battery_update(battery, false);
>>>> - if (result)
>>>> +
>>>> + /*
>>>> + * Some machines'(E,G Lenovo Z480) ECs are not stable
>
> Just a reminder.
>
> This statement may not be true.
> The issue may be caused by the EC driver itself.
> So we need to investigate.

Not sure. The bug doesn't happen every time. 5-10% during boot up.

>
>>>> + * during boot up and this causes battery driver fails to be
>>>> + * probed due to failure of getting battery information
>>>> + * from EC sometimes. After several retries, the operation
>>>> + * may work. So add retry code here and 20ms sleep between
>>>> + * every retries.
>>>> + */
>>>> + while (acpi_battery_update(battery, false) && retry--)
>
> If EC hardware is stable, why we need to do retry here?
>

Yes, if it can work normally every time, we don't need retry here.


> Thanks and best regards
> -Lv
>
>>>> + msleep(20);
>>>> + if (!retry) {
>>>> + result = -ENODEV;
>>>> goto fail;
>>>> + }
>>>> +
>>>
>>> I think you want --retry and not retry--.
>>
>> My original purpose is to retry 5 times after the first try fails.
>> If use "--retry" here, it just retries 4 times.
>>
>>> Otherwise it's possible for the
>>> final call to acpi_battery_update() to succeed and now it's returning
>>> -ENODEV.
>>>
>>
>> Yes, it maybe and I will change code like the following.
>>
>> while ((result = acpi_battery_update(battery, false)) && retry--)
>> msleep(20);
>> if (result)
>> goto fail;
>>
>>
>> --
>> Best regards
>> Tianyu Lan
>> --
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--
Best regards
Tianyu Lan
--
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