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> From: "Mcgrath, Jim" <[EMAIL PROTECTED]> > Date: Monday - January 28, 2002 5:26 PM Thank you for this new nutshell, I feel we continue ever to clue me in, however slowly. > The device is required > to quietly absorb any extra bytes > the host send during a UDMA data out > (that's in the ATA standard). I don't think this is widely appreciated. Inside the device, this turns into FIFOs that are normally empty at Status time occasionally being nonempty. I have a personal history of pain with people assuming of course FIFOs are empty at this time: Ata/pi implementations that too aggressively change to moving status from moving data can cut data short with this kind of assumption. > since no harm was done Maybe. > why would anyone care > about correcting it anyway I'd like to give the device the option of saying specifically how many bytes it chose to quietly copy into the void. I want this particularly for the case of a total byte count of data that is odd, since in that case nonzero residue is unavoidable. But if we're going to solve that with a residue visible on the bus, then I'd like to see us restore the fully arbitrary byte count negotiations of Pio at the same time. All we have to do is to allow permit the reported residual byte count to be as large as X * 2 + 1, where X is the receiver-side halt-the-transfer indeterminacy designed into Atapi UDma. Pat LaVarre Subscribe/Unsubscribe instructions can be found at www.t13.org.
