linux-kernel - Re: [PATCH] ACPI/Battery: Retry to get Battery information if failed during probing

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Date:	Tue, 17 Jun 2014 09:27:54 +0800
From:	Lan Tianyu <tianyu.lan@...el.com>
To:	David Rientjes <rientjes@...gle.com>
CC:	rjw@...ysocki.net, lenb@...nel.org, naszar@...ru,
	linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ACPI/Battery: Retry to get Battery information if failed
 during probing

On 2014年06月17日 09:27, David Rientjes wrote:
> On Mon, 16 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
>>>> +        * 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--)
>>>> +               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;
>>
> 
> Looks good.
> 

Great. Thanks for review. :)


-- 
Best regards
Tianyu Lan
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