Re: System hangs when using USB 3.0 HD with on Ubuntu

Sarah Sharp
2010-04-21T17:41:01Z

On Wed, Apr 21, 2010 at 12:18:51PM -0400, Martin K. Petersen wrote:
> >>>>> "Alan" == Alan Stern <stern@rowland.harvard.edu> writes:
>
> I'm guessing Doug is out today because he didn't forward the note
> below. Just passing the info along...
>
>
> >> It is needed by the transport protocol(s).
>
> Alan> I don't understand; can you explain more fully? Which transport
> Alan> protocol(s) need to use the Sector Count? The USB transport
> Alan> protocol doesn't; it encodes the transfer length in a wrapper.
> Alan> The bridge chip should interpret the wrapper instead of looking
> Alan> inside the SAT command.
>
> Doug posted to the T10 list and here's what Jim Hatfield from Seagate
> responded:
>
> For ATA (SATA or PATA), the Count field should NEVER be zero,
> because neither interface supports zero-length data transfer for
> any protocol (dma, pio, etc).
>
> In ATA, 'N/A' is defined the way it is because there are some
> ancient implementations for which there are vendor specific
> differences.

So, if Jim is correct, then this may not be a bug in the Buffalo device?
Or is the phase error in the status of the CSW still an incorrect
response after a stall on what the device thinks is an invalid command?

Sarah Sharp