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From: Sergei Shtylyov <sshtylyov@ru.mvista.com>
To: Robert Hancock <hancockr@shaw.ca>
Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ide: Fix ata_id_has_dword_io to return DWORD I/O   support properly
Date: Sat, 20 Dec 2008 16:25:05 +0300	[thread overview]
Message-ID: <494CF231.4020000@ru.mvista.com> (raw)
In-Reply-To: <494C512B.6090304@shaw.ca>

Hello.

Robert Hancock wrote:

>>> This seems like a risky assumption...
>>
>> Its wrong on various counts
>>
>> - ata_id_major_version can't tell early ATA versions apart
>> - on anything later than the early ISA IDE paddles (the ones that
>> basically were just bus decoders) its invisible to the drive
>>
>> Except for legacy ISA bus controllers (and even there it is 
>> questionable)
>> I would favour simply ignoring it.
>
> 32-bit IO wouldn't work on any ISA controller, would it? What happens 
> if you do 32-bit IO port access on something on the ISA bus?

   TTBOM, depending on what's driven by device on -IOCS16, this will 
translate into 2, 3, or 4 cycles at the successive addresses. In case of 
the IDE data register, this should translate into one 16-bit cycle at 
0x1x0, one 8-bit cycle at 0x1x1, and one 8-bit cycle at 0x1x2 which is 
of course not what anybody would want...

WBR, Sergei



  reply	other threads:[~2008-12-20 13:25 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <494A5BBF.8000807@inf.tu-dresden.de>
2008-12-18 17:08 ` [PATCH] ide: Fix ata_id_has_dword_io to return DWORD I/O support properly Jeff Garzik
2008-12-18 17:24   ` Sergei Shtylyov
2008-12-18 20:42     ` Bartlomiej Zolnierkiewicz
2008-12-18 22:40       ` Alan Cox
2008-12-18 23:13         ` Bartlomiej Zolnierkiewicz
2008-12-19 10:50           ` Alan Cox
2008-12-19 19:30             ` Bartlomiej Zolnierkiewicz
2008-12-20  0:10               ` Alan Cox
2008-12-19 11:31         ` Sergei Shtylyov
2008-12-19 11:34           ` Sergei Shtylyov
2008-12-18 18:10   ` Alan Cox
2008-12-20  1:58     ` Robert Hancock
2008-12-20 13:25       ` Sergei Shtylyov [this message]
2008-12-22 20:16         ` Sergei Shtylyov

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