Re: [PATCH + RFC] Beginning of some updates to scsi mid layer

Matthew Jacob
2002-06-29T10:37:26Z

On Sat, 29 Jun 2002, Doug Ledford wrote:

> On Fri, Jun 28, 2002 at 07:04:28PM -0700, Matthew Jacob wrote:
> >
> > FWIW, Bob Snively (on T10 commitee) has always claimed that the correct
> > response to QUEUE FULL is immediate command resubmission (i.e., *don't* wait
> > for a command to complete (the QFULL may have resulted from commands being
> > processed for *another* initiator), and *don't* a period of time for things to
> > 'get better').
> >
> > I'm not sure agree with this 100%, but he might have a point.
>
> No, absolutely not! Faster drivers are capable of restarting commands on
> the bus so fast that in this scenario they can flood the bus with
> selection, command, queue full sequences and not allow *any* commands to
> complete because the bus is always tied up (this was, in fact, one of the
> reasons that I had to put the queue handling code in the aic7xxx driver
> when I did).

Yeah- I thought of that. But that problem actually goes away somewhat with FC
(&& QAS maybe).