linux-kernel - Re: [PATCH v2 1/3] thermal: tegra: continue if sensor register fails

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Date:   Thu, 22 Nov 2018 14:07:31 +0100
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Wei Ni <wni@...dia.com>, thierry.reding@...il.com,
        linux-tegra@...r.kernel.org
Cc:     rui.zhang@...el.com, edubezval@...il.com,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/3] thermal: tegra: continue if sensor register fails

On 22/11/2018 08:10, Wei Ni wrote:
> 
> 
> On 21/11/2018 8:51 PM, Daniel Lezcano wrote:
>> On 21/11/2018 11:23, Wei Ni wrote:
>>>
>>>
>>> On 21/11/2018 4:55 PM, Daniel Lezcano wrote:
>>>> On 13/11/2018 11:06, Wei Ni wrote:
>>>>> Don't bail when a sensor fails to register with the
>>>>> thermal zone and allow other sensors to register.
>>>>> This allows other sensors to register with thermal
>>>>> framework even if one sensor fails registration.
>>>>
>>>> I'm not sure if ignoring the error is really safe. Can you describe the
>>>> real situation you want to overcome ? How do you differentiate critical
>>>> sensors ?
>>>
>>> The driver will always try to register 4 thermal zones, including cpu,
>>> gpu, mem and pll, but if the dts file doesn't set the corresponding
>>> sensors, then the register will be failed.
>>> Normally, the dts file will set all 4 sensors, but there may have some
>>> platform doesn't support them all. So we post this patch.
>>
>> Ignoring errors is not the way to go to support different platforms. Fix
>> the DT.
> 
> The issue isn't in DT file. The Tegra soc thermal include 4 sensors:
> cpu, gpu, mem, pll. But in some platforms, for example, we may only need
> to support 2 sensors, such as cpu and gpu, so we only configure these
> two senors in DT file. But the driver will always try to register 4
> sensors, cpu/gpu/mem/pll, so mem and pll will be registered failed. So
> in this case we need to ignoring the failure, and continue to enable the
> driver.

You can fix this by changing the driver to support the platform and
register the sensor you are interested in.

Ignoring errors is not a good idea.


>>> BTW, what do you mean "critical sensors"? We will set critical trip temp
>>> for all sensors.
>>
>> I meant sensor for thermal zone getting really high temperature.
> 
> We doesn't have the critical sensors. We set the critical trip temp for
> all registered sensors. And these trip temp is set to the Tegra
> hardware. So it mean if the temperature reached the critical trip point,
> then the system will be shutdown directly.
> 
>>
>>
>>>>> Signed-off-by: Wei Ni <wni@...dia.com>
>>>>> ---
>>>>>  drivers/thermal/tegra/soctherm.c | 8 +++++---
>>>>>  1 file changed, 5 insertions(+), 3 deletions(-)
>>>>>
>>>>> diff --git a/drivers/thermal/tegra/soctherm.c b/drivers/thermal/tegra/soctherm.c
>>>>> index ed28110a3535..a824d2e63af3 100644
>>>>> --- a/drivers/thermal/tegra/soctherm.c
>>>>> +++ b/drivers/thermal/tegra/soctherm.c
>>>>> @@ -1370,9 +1370,9 @@ static int tegra_soctherm_probe(struct platform_device *pdev)
>>>>>  							 &tegra_of_thermal_ops);
>>>>>  		if (IS_ERR(z)) {
>>>>>  			err = PTR_ERR(z);
>>>>> -			dev_err(&pdev->dev, "failed to register sensor: %d\n",
>>>>> -				err);
>>>>> -			goto disable_clocks;
>>>>> +			dev_warn(&pdev->dev, "failed to register sensor %s: %d\n",
>>>>> +				 soc->ttgs[i]->name, err);
>>>>> +			continue;
>>>>>  		}
>>>>>  
>>>>>  		zone->tz = z;
>>>>> @@ -1434,6 +1434,8 @@ static int __maybe_unused soctherm_resume(struct device *dev)
>>>>>  		struct thermal_zone_device *tz;
>>>>>  
>>>>>  		tz = tegra->thermctl_tzs[soc->ttgs[i]->id];
>>>>> +		if (!tz)
>>>>> +			continue;
>>>>>  		err = tegra_soctherm_set_hwtrips(dev, soc->ttgs[i], tz);
>>>>>  		if (err) {
>>>>>  			dev_err(&pdev->dev,
>>>>>
>>>>
>>>>
>>
>>


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