[7361] in linux-scsi channel archive
Re: Long SCSI command
daemon@ATHENA.MIT.EDU (Douglas Gilbert)
Sun Oct 17 22:49:46 1999
Message-ID: <380A8BCC.F5C8258E@interlog.com>
Date: Sun, 17 Oct 1999 22:54:04 -0400
From: Douglas Gilbert <dgilbert@interlog.com>
MIME-Version: 1.0
To: warren <warren@infortrend.com.tw>
CC: linux-scsi@vger.rutgers.edu
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warren wrote:
>
> Hi,
> Is there a way to send SCSI commands of length 16 bytes? Or which
> version of SG driver is applicable ?
Warren,
The simple answer is no. Getting sg to accept 16 byte commands
is not the problem (a test version does it but to no avail).
Unfortunately the mid level sets the maximum SCSI command length
at 12 bytes (in the Scsi_Cmnd structure) and copies it around
several places with temporary 12 bytes arrays. To make things
worse, quite a lot of SCSI adapter drivers make the same assumption.
I contemplated making the changes to the mid-level to expand
this limit while doing some other patches (for 64 byte sense
buffers and DMA residual count) but wondered whether it was
worth the trouble.
Do you have a work-around for 16 byte SCSI commands?
Doug Gilbert
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