Re: [PATCH] ide: Fix ata_id_has_dword_io to return DWORD I/O support properly

Sergei Shtylyov
2008-12-20T13:25:26Z

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