linux-kernel - Re: [PATCH -next] i2c: Fix missing pci_disable_device() on error in ali1535

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Date:   Tue, 8 Jun 2021 19:30:38 +0800
From:   Samuel Zou <zou_wei@...wei.com>
To:     Jean Delvare <jdelvare@...e.de>
CC:     <linux-i2c@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH -next] i2c: Fix missing pci_disable_device() on error in
 ali1535_setup()

Hi Jean,

Thanks for your review and detailed explanation.

On 2021/6/8 17:46, Jean Delvare wrote:
> Hi Wei,
> 
> On Mon, 07 Jun 2021 11:21:08 +0800, Zou Wei wrote:
>> Fix the missing pci_disable_device() before return
>> from ali1535_setup() in the error handling case.
>>
>> Reported-by: Hulk Robot <hulkci@...wei.com>
>> Signed-off-by: Zou Wei <zou_wei@...wei.com>
>> ---
>>   drivers/i2c/busses/i2c-ali1535.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/i2c/busses/i2c-ali1535.c b/drivers/i2c/busses/i2c-ali1535.c
>> index fb93152..bdbaf79 100644
>> --- a/drivers/i2c/busses/i2c-ali1535.c
>> +++ b/drivers/i2c/busses/i2c-ali1535.c
>> @@ -206,6 +206,7 @@ static int ali1535_setup(struct pci_dev *dev)
>>   exit_free:
>>   	release_region(ali1535_smba, ALI1535_SMB_IOSIZE);
>>   exit:
>> +	pci_disable_device(dev);
>>   	return retval;
>>   }
>>   
> 
> We don't actually want to disable the PCI device. Maybe it was already
> enabled before the driver was loaded, and maybe the BIOS needs the
> device when the system is being shut down. You'll notice that we do not
> call pci_disable_device(dev) in ali1535_remove(), so there's no reason
> to do it in the error path.
> 
> As a matter of fact the i2c-i801 driver, which is used on the same kind
> of hardware, has the following note in its remove function:
> 
> 	/*
> 	 * do not call pci_disable_device(dev) since it can cause hard hangs on
> 	 * some systems during power-off (eg. Fujitsu-Siemens Lifebook E8010)
> 	 */
> 
> So this is a nack from me, sorry.
>