linux-kernel - Re: [PATCH] devfreq: tegra: fix error code in tegra_devfreq

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Message-ID: <df35dc5e-0a8f-0022-be20-36be38fbf83b@nvidia.com>
Date:   Mon, 3 Jul 2017 13:22:04 +0100
From:   Jon Hunter <jonathanh@...dia.com>
To:     "Gustavo A. R. Silva" <garsilva@...eddedor.com>
CC:     MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        "Thierry Reding" <thierry.reding@...il.com>,
        <linux-pm@...r.kernel.org>, <linux-tegra@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] devfreq: tegra: fix error code in tegra_devfreq_probe()


On 03/07/17 12:59, Gustavo A. R. Silva wrote:
> Hi Jon,
> 
> Quoting Jon Hunter <jonathanh@...dia.com>:
> 
>> On 30/06/17 08:22, Gustavo A. R. Silva wrote:
>>> Print and propagate the return value of platform_get_irq on failure.
>>>
>>> Signed-off-by: Gustavo A. R. Silva <garsilva@...eddedor.com>
>>> ---
>>>  drivers/devfreq/tegra-devfreq.c | 6 +++---
>>>  1 file changed, 3 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/devfreq/tegra-devfreq.c
>>> b/drivers/devfreq/tegra-devfreq.c
>>> index 214fff9..ae71215 100644
>>> --- a/drivers/devfreq/tegra-devfreq.c
>>> +++ b/drivers/devfreq/tegra-devfreq.c
>>> @@ -688,9 +688,9 @@ static int tegra_devfreq_probe(struct
>>> platform_device *pdev)
>>>      }
>>>
>>>      irq = platform_get_irq(pdev, 0);
>>> -    if (irq <= 0) {
>>> -        dev_err(&pdev->dev, "Failed to get IRQ\n");
>>> -        return -ENODEV;
>>> +    if (irq < 0) {
>>
>> The changelog does not describe the above change and if/why this is ok.
>> However, the original test looks fine to me and so I don't see a need to
>> change this.
>>
> 
> You are right about the changelog. I think this one is much better:
> 
> platform_get_irq() returns an error code, but the tegra-devfreq
> driver ignores it and always returns -ENODEV. This is not correct,
> and prevents -EPROBE_DEFER from being propagated properly.
> 
> Notice that platform_get_irq() no longer returns 0 on error:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e330b9a6bb35dc7097a4f02cb1ae7b6f96df92af

Yes the above should be added to the changelog.

Looks like someone should update the following for consistency too ...

141 int platform_irq_count(struct platform_device *dev)
142 {
143         int ret, nr = 0;
144
145         while ((ret = platform_get_irq(dev, nr)) >= 0)
146                 nr++;

> 
> Print error message and propagate the return value of
> platform_get_irq on failure.
> 
> What do you think?
Fine with me.

Thanks!
Jon

-- 
nvpublic