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On Fri, 22 Jun 2001 12:12:16 -0600, Pat LaVarre wrote:
[Kind of off topic for T13 but Pat is writing about a host that
trusts a device to tell the host about the details of a data
transfer.]
>I see this back as far as Scsi ... but I hear it's nearly built-in to FireWire.
>I can't get anyone to give me a straight answer: best as I can tell,
>any FireWire device can go to any PCI bus address.
Not strictly true. A Quadlet or Block Read/Write to a "1394 48-bit
memory address" that is outside of the bounds of the current
operation or not defined for the target device should fail. But 1394
has many many data integrity problems, too many to list here!
>I'm hoping if I press this point I'll find there are some bounds.
>Maybe there are bounds in the FireWire host controller if the
>device at least succeeds in persuading the host to recognise
>it as a mass storage device that has no business accessing memory at random.
If the host controller is an OHCI then it is mostly up to the host
software drivers to disallow illegal accesses like my favorite:
Writing data into the host's data transfer page tables!
*** Hale Landis *** [EMAIL PROTECTED] ***
*** Niwot, CO USA *** www.ata-atapi.com ***
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