This message is from the T13 list server.

On Mon, 15 Apr 2002 11:38:00 -0600, Pat LaVarre wrote:
>This message is from the T13 list server.
>My proposal (November?) last year was:

Does it have a T13 document number?

>a) Flip a bit in the op xA1 IdentifyPacketDevice to say you are device that
>bothers to report the bus residue, even for Dma, not just for Pio.

OK.

>b) Report the bus residue in x1F5:1F4 ByteCount at 
>BSY DRQ C/D I/O = 0 0 c i StatusIn time.
>c) Also report x1F3 SectorNumber = x80 to say the device copied data In. 
>Report x1F3 SectorNumber = x00 to say the device copied data Out.

Why do you need all 16-bits of the Byte Count registers to report a
residue value that can only be 0 or 1?

Isn't the device reporting the data direction at the end of the
command a little late? Hasn't the command failed, probably with some
timeout error, long before the end of the command is reached?

>In all the Atapi device silicon I know, this is a firmware change only, no
>silicon change required.  Silicon that automagically reports Good status
>despite the Atapi Data Fifo being not empty would have to learn to check for
>that (rare) condition.

The registers you want to use are currently defined as having an 'na'
value at the end of a PACKET command. Your company could just put
this information there a 'vendor specific' data. Maybe you company is
currently shipping devices that do this? Yes? No?



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



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