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Subject: Re: [PATCH 1/4] pata_parport: fix pata_parport_devchk
To:     Ondrej Zary <linux@zary.sk>, Sergey Shtylyov <s.shtylyov@omp.ru>
Cc:     Damien Le Moal <damien.lemoal@opensource.wdc.com>,
        Sudip Mukherjee <sudipm.mukherjee@gmail.com>,
        Christoph Hellwig <hch@lst.de>, Tim Waugh <tim@cyberelk.net>,
        linux-parport@lists.infradead.org, linux-ide@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20230930191511.24994-1-linux@zary.sk>
 <20230930191511.24994-2-linux@zary.sk>
 <d040b3f7-4222-a027-34d0-5cf62aa63605@omp.ru>
 <202310031907.45632.linux@zary.sk>
From:   Sergei Shtylyov <sergei.shtylyov@gmail.com>
Message-ID: <a3b4dc62-20f7-4900-b9db-87edc9131063@gmail.com>
Date:   Tue, 3 Oct 2023 20:18:21 +0300
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On 10/3/23 8:07 PM, Ondrej Zary wrote:
[...]

>>> There's a 'x' missing in 0x55 in pata_parport_devchk(), causing the
>>> detection to always fail. Fix it.
>>>
>>> Signed-off-by: Ondrej Zary <linux@zary.sk>
>>
>>    I think we need a Fixes: tag here...
>>
>>> ---
>>>  drivers/ata/pata_parport/pata_parport.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/ata/pata_parport/pata_parport.c b/drivers/ata/pata_parport/pata_parport.c
>>> index 1af64d435d3c..258d189f42e5 100644
>>> --- a/drivers/ata/pata_parport/pata_parport.c
>>> +++ b/drivers/ata/pata_parport/pata_parport.c
>>> @@ -64,7 +64,7 @@ static bool pata_parport_devchk(struct ata_port *ap, unsigned int device)
>>>  	pi->proto->write_regr(pi, 0, ATA_REG_NSECT, 0xaa);
>>>  	pi->proto->write_regr(pi, 0, ATA_REG_LBAL, 0x55);
>>>  
>>> -	pi->proto->write_regr(pi, 0, ATA_REG_NSECT, 055);
>>> +	pi->proto->write_regr(pi, 0, ATA_REG_NSECT, 0x55);
>>
>>    Oh, Gawd! How did this ever work?! :-/
>>    This bug seems to predate the Big PARIDE move...
> 
> This code was not present in PARIDE - it's my bug.

   Yes, I finally figured -- hence the Fixes: tag I suggested later....

> The function is a clone of ata_devchk() without direct port access.

   The libata's taskfile methods suck big time -- I even used to have
the plans to clean this stuff up at some point...

> It's called only from softreset so nobody notices the breakage until something goes wrong. The CD-865 drive needs a reset to start working.

   I thought the SRST reset is used at the initial detection phase as well...

MBR, Sergey