Re: Emulex QT13 hangs (Was: CMD fixes in 11?)

[Dave McGuire <mcguire%neurotica.com@localhost>]

On 5/4/26 05:20, Hans Rosenfeld wrote:
> > > Does it still hang on -11?
> > >
> > > If so, can you perhaps point me to a bug entry or a mailing list post
> > > that describes the problem in more detail?
> >
> >    I was finally able to get to this.  It still hangs in -11 RC3.  Again it's
> > an Emulex QT13, not a CMD controller.  The machine is a 4000-705A.
> > Everything runs fine otherwise.
>
> Can elaborate a bit how the problem with the Emulex QT13 manifests
> itself? The QT13 can be configured to do TMSCP or to be compatible with
> a TSV05, but I presume your's is configured to do TMSCP. Do you have
> tape drive connected to it?

  Yes, it's got a drive attached.  It's set up for TMSCP; under VMS it 
shows up as a TU81, and it works.

  Just doing a "tar -cvf" hangs the shell (not the machine), ^C won't 
interrupt it, and I can't kill the process from another shell.

> The CMD MSCP problem was caused by /boot setting up QBus mappings for
> the controller it was booted from, and the kernel clearing them without
> the controller being reset before doing so. This lead to a firmware
> lockup in the controller, so it wouldn't respond to the kernel driver
> anymore. None of this happened when booting from a different controller
> (such as from the net), because then the MSCP controller remained
> inactive until first accessed by the kernel driver. The system didn't
> hang in either case.

  That was some excellent sleuthing there!

           -Dave

--
Dave McGuire, AK4HZ
New Kensington, PA