linux-kernel - Re: 答复: [PATCH v3] thermal: ti-soc-thermal: Remove unused variable 'val'

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Message-ID: <c7d67490-06cd-f15a-3972-3db4d5812a69@linaro.org>
Date:   Thu, 22 Apr 2021 15:50:25 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     linruizhe <linruizhe@...wei.com>, Tony Lindgren <tony@...mide.com>
Cc:     Greg KH <gregkh@...uxfoundation.org>,
        "rui.zhang@...el.com" <rui.zhang@...el.com>,
        "edubezval@...il.com" <edubezval@...il.com>,
        "j-keerthy@...com" <j-keerthy@...com>,
        "amitk@...nel.org" <amitk@...nel.org>,
        "eballetbo@...il.com" <eballetbo@...il.com>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: 答复: [PATCH v3] thermal: ti-soc-thermal: Remove unused variable 'val'


Hi Lin,


On 22/04/2021 14:39, linruizhe wrote:
> Hi Daniel,
> 
> Do I need to make more changes to this patch?

No, it is fine. I've applied it.

Thanks

  -- Daniel


> Thanks
>  
>   -Lin Ruizhe
> 
> -----邮件原件-----
> 发件人: Daniel Lezcano [mailto:daniel.lezcano@...aro.org] 
> 发送时间: 2021年4月21日 19:37
> 收件人: Tony Lindgren <tony@...mide.com>
> 抄送: Greg KH <gregkh@...uxfoundation.org>; linruizhe <linruizhe@...wei.com>; rui.zhang@...el.com; edubezval@...il.com; j-keerthy@...com; amitk@...nel.org; eballetbo@...il.com; linux-pm@...r.kernel.org; linux-omap@...r.kernel.org; linux-kernel@...r.kernel.org
> 主题: Re: [PATCH v3] thermal: ti-soc-thermal: Remove unused variable 'val'
> 
> 
> Hi Tony,
> 
> thanks for testing
> 
>   -- Daniel
> 
> On 21/04/2021 11:37, Tony Lindgren wrote:
>> * Daniel Lezcano <daniel.lezcano@...aro.org> [210421 09:07]:
>>> On 21/04/2021 10:49, Greg KH wrote:
>>>> On Wed, Apr 21, 2021 at 04:42:56PM +0800, Lin Ruizhe wrote:
>>>>> The variable 'val'in function ti_bandgap_restore_ctxt is the 
>>>>> register value of read bandgap registers. This function is to 
>>>>> restore the context. But there is no operation on the return value 
>>>>> of this register, so this block is redundant. Hulk robot scans this 
>>>>> warning.This commit remove the dead code.
>>>>>
>>>>> Reported-by: Hulk Robot <hulkci@...wei.com>
>>>>> Fixes: b87ea759a4cc ("staging: omap-thermal: fix context restore 
>>>>> function")
>>>>> Signed-off-by: Lin Ruizhe <linruizhe@...wei.com>
>>>>> ---
>>>>> v3:
>>>>> -Add Fixes tag and more accurate commit message in this patch.
>>>>> v2:
>>>>> -As suggest remove the whole unuesed block in fuction  
>>>>> ti_bandgap_restore_ctxt
>>>>>
>>>>>  drivers/thermal/ti-soc-thermal/ti-bandgap.c | 4 ----
>>>>>  1 file changed, 4 deletions(-)
>>>>>
>>>>> diff --git a/drivers/thermal/ti-soc-thermal/ti-bandgap.c 
>>>>> b/drivers/thermal/ti-soc-thermal/ti-bandgap.c
>>>>> index d81af89166d2..684ffb645aa9 100644
>>>>> --- a/drivers/thermal/ti-soc-thermal/ti-bandgap.c
>>>>> +++ b/drivers/thermal/ti-soc-thermal/ti-bandgap.c
>>>>> @@ -1142,14 +1142,10 @@ static int ti_bandgap_restore_ctxt(struct ti_bandgap *bgp)
>>>>>  	for (i = 0; i < bgp->conf->sensor_count; i++) {
>>>>>  		struct temp_sensor_registers *tsr;
>>>>>  		struct temp_sensor_regval *rval;
>>>>> -		u32 val = 0;
>>>>>  
>>>>>  		rval = &bgp->regval[i];
>>>>>  		tsr = bgp->conf->sensors[i].registers;
>>>>>  
>>>>> -		if (TI_BANDGAP_HAS(bgp, COUNTER))
>>>>> -			val = ti_bandgap_readl(bgp, tsr->bgap_counter);
>>>>
>>>> Are you sure that this hardware does not require this read to happen 
>>>> in order for it to work properly?
>>>
>>> Yes, initially we had the same concern but we were unable to find 
>>> anything specific in the history. The commit mentioned above removed 
>>> the user of the 'val' code but without removing this block of code.
>>>
>>> When looking at the current code, it really looks like an oversight.
>>
>> Yes so it seems.
>>
>>> There is nothing in the commit's changelog referring to a need of 
>>> reading the counter register but perhaps I'm wrong because I'm not 
>>> sure to understand correctly the changelog.
>>>
>>>> Lots of hardware does need this, have you tested this?
>>
>> I just tested this on omap3 logicpd torpedo devkit that can do off 
>> during idle and reading /sys/class/thermal/thermal_zone0/temp works. 
>> So feel free to add:
>>
>> Reviewed-by: Tony Lindgren <tony@...mide.com>
>> Tested-by: Tony Lindgren <tony@...mide.com>
> 
> Thanks for testing
> 
> 
> --
> <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs
> 
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> 


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