Re: [usb-storage] USB storage devices and SAT

[Boaz Harrosh <bharrosh@xxxxxxxxxxx>]

Boaz Harrosh wrote:
> Douglas Gilbert wrote:
>> The "correct" maximum value (SPC-3 and draft SPC-4) is 252.
>> Since SPC-3 the recommended maximum length for the basic
>> SCSI commands that have a 1 byte allocation length field was
>> altered from 255 to 252. This is to be a little friendlier
>> to transports that move data in 4 byte units across their
>> transport. Guessing a bit here but SATA, SAS and FCP fall
>> into that group of transports.
> 
> 252 + 8 bytes header for REQUEST_SENSE command. So total
> 260 buffer size. (Last I look)
> 

OK you are right 252 allocation length max, specified at
REQUEST_SENSE CDB. The sense_buffer structure itself has 
252 + 8 restriction which got me confused. In OSD we
have large sense payload that can get truncated by these
values.

Boaz
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