What is the correct response to an INQUIRY with EVPD sent to an invalid LUN?

Paul Hughes phughes at solidfire.com
Wed Jan 7 13:24:48 PST 2015

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I've always taken the approach that an Inquiry command with EVPD=0 should
complete normally (return Standard Inquiry data) when issued to an invalid
LUN, but if EVPD=1 the Inquiry command should return Check Condition status
and sense data of "Illegal Request, Logical Unit Not Supported".
On Wed, Jan 7, 2015 at 1:26 PM, Chris Moore <Chris.Moore at emulex.com> wrote:
> * From the T10 Reflector (t10 at t10.org), posted by:
> * Chris Moore <Chris.Moore at Emulex.Com>
> *
> Looking at SPC-5, 6.5.1 says "An enable vital product data (EVPD) bit set
> to one specifies that
> the device server shall return the vital product data specified by the
> PAGE CODE field."
> It goes on to say that if the LUN is invalid then the PERIPHERAL QUALIFIER
> should be set
> according to Table 138.  In my case that's 011b for the Qualifier and 1fh
> for the device type.
> What should follow that?   The fact that the EVPD bit is set suggests that
> the returned data
> should be a VPD page, not a Standard INQUIRY.  7.7.2 says the page code
> must be set to
> the page code that was requested.
> In the case of page 83h, says if I return page 83h I shall
> include at least one
> designation descriptor.
> So in this case, do I return a VPD page with code 83h and zero page
> length?  Do I return
> a Standard Inquiry?
> sg_inq seems unhappy if it doesn't get back a VPD page with a page code of
> 83h.	It
> also seems unhappy with a page length of zero.  My JDSU analyzer assumes
> that since
> the INQUIRY had EVPD set then the response must be a VPD page.
> Any guidance on the correct way to respond to this would be helpful.
> Chris Moore
> Principal Engineer
> Emulex
> *
> * For T10 Reflector information, send a message with
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*Paul HughesSenior Software Engineer, SolidFire, Inc.*
e: phughes at solidfire.com
*Advancing the way the world uses the cloud

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