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Message-ID: <3045fde1-2d5b-e731-ef18-6cf3f0987259@opensource.wdc.com>
Date:   Wed, 13 Apr 2022 12:42:20 +0900
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Subject: Re: [BUG] ata: pata_marvell: Warning when probing the module
Content-Language: en-US
To:     Zheyu Ma <zheyuma97@gmail.com>
Cc:     Sergey Shtylyov <s.shtylyov@omp.ru>, linux-ide@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
References: <CAMhUBjkVME8D5KsHvT=uddBsW_Bh6wr7qeXS=UpQD4LgPmHffQ@mail.gmail.com>
 <05433153-0424-ab66-1573-993d0490c5bc@opensource.wdc.com>
 <CAMhUBj=JsiHnnQzrqPKzA=Z2+589Ju_HE0cFKyon58Fk0waeAQ@mail.gmail.com>
From:   Damien Le Moal <damien.lemoal@opensource.wdc.com>
Organization: Western Digital Research
In-Reply-To: <CAMhUBj=JsiHnnQzrqPKzA=Z2+589Ju_HE0cFKyon58Fk0waeAQ@mail.gmail.com>
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On 4/12/22 15:34, Zheyu Ma wrote:
> On Mon, Apr 11, 2022 at 7:53 AM Damien Le Moal
> <damien.lemoal@opensource.wdc.com> wrote:
>>
>> On 4/10/22 15:30, Zheyu Ma wrote:
>>> Hello,
>>>
>>> I found a bug in the pata_marvell module.
>>> When probing the driver, it seems to trigger the error path and
>>> executes the function marvell_cable_detect(), but the
>>> 'ap->ioaddr.bmdma_addr' is not initialized, which causes a warning.
>>
>> I do not have this hardware so I cannot debug this. Please debug it and
>> send a patch. bmdma_addr is normally set in ata_pci_bmdma_init(), but some
>> drivers set it manually in their probe functions. No idea about the
>> marvell driver, I have not checked it.
> 
> To be honest I don't have a good solution to this problem, because
> other drivers don't have similar behavior. The marvell driver doesn't
> even initialize 'bmdma_addr' before calling 'cable_detect'.

Then this is the bug that needs to be fixed, no ?

> So a simple idea I have is to check if 'bmdma_addr' is 0 before
> reading it and if so return the error code ATA_CBL_NONE.

And if indeed, even after it is initialized it is still 0, then yes, this
change seems sensible.

> 
> Zheyu Ma


-- 
Damien Le Moal
Western Digital Research