mpr(4) and disable_eedp

[Kenneth D. Merry]

On Mon, Sep 10, 2018 at 09:47:00 -0700, Lee Brown wrote:
> On Thu, Nov 16, 2017 at 6:28 AM, Kenneth D. Merry <ken at freebsd.org> wrote:
> 
> > On Wed, Nov 15, 2017 at 12:24:47 -0800, Lee Brown wrote:
> > > I'm looking to build a SAS array with a Dell MD1420.  It will be attached
> > > via a SAS 9300-414E HBA in a Dell R330.
> >
> > In theory it should be fine.  I haven't used a Dell enclosure recently, but
> > from posts here, it seems that they like to turn on Type 2 Protection
> > Information on the drives.  (Assuming you buy the drives from Dell.)
> >
> > If they do that, you can either reformat, or see the patch here for the
> > mpr(4) driver to disable using protection information:
> >
> > https://docs.freebsd.org/cgi/getmsg.cgi?fetch=308820+0+
> > archive/2017/freebsd-scsi/20171022.freebsd-scsi
> >
> > I have been using this patch in production on an 11.1 kernel with great
> success.
> 
> I'm upgrading to 11.2 today and am wondering what's required to push this
> into the source tree (so I can be lazy next time and not have to patch)?  I
> can provide testing and maybe the MD1420 could be added to the officially
> supported hardware list?  Let me know how I could help.
> 
> BTW, there's a typo in the patch for mpr.c "dsiable" should be "disable":
> +    OID_AUTO, "dsiable_eedp", CTLFLAG_RD, &sc->disable_eedp, 0,

I put in a slightly different version of the change in March 2018 that just
disables Type 2 data protection:

https://svnweb.freebsd.org/base?view=revision&revision=331422

I MFCed it a few days later, so 11.2 should work without a patch.  If it
doesn't, let me know.  There is no sysctl/tunable variable in the new version.

To get the Dell MD1420 put in as supported hardware, you could probably put
in a documentation bug report, the links are here:

https://www.freebsd.org/support.html

Ken
-- 
Kenneth Merry
ken at FreeBSD.ORG