This message is from the T13 list server.

I am wondering whether there is a consistent behavior among the ATA/ATAPI
devices when the PIO port got accessed during DMA operation?  If nothing was
defined for such condition in ATA/ATAPI spec, it will be no meaning to
"define" such access in host adapter standard.

Raymond Liu

-----Original Message-----
From: Hale Landis [mailto:[EMAIL PROTECTED]]
Sent: Friday, April 12, 2002 1:42 PM
To: [EMAIL PROTECTED]
Subject: RE: [t13] the Pio port accesses that occur during Dma


This message is from the T13 list server.


On Fri, 12 Apr 2002 11:49:59 -0700, [EMAIL PROTECTED] wrote:
>This message is from the T13 list server.
>Is there anywhere in the specification indicate that the host hardware
>should allow the driver to perform PIO operation while a DMA command is
>active?

It is part of the "folklore". It works that way because old ISA DMA
engines worked that way. We have the chance now to document it (or
outlaw it) in the proposed host adapter standards document.

As I just told someone else, there is lots of test software and eval
software and even BIOS/OS "power management" drivers that read status
causing this condition to happen.



*** Hale Landis *** www.ata-atapi.com ***


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