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

Sergei Shtylyov
2008-12-22T20:16:21Z

Hello, I 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...

The 8-bit cycles would be at ports 0x1x2 and 0x1x3, of course. :-)

MBR, Sergei