> -----Original Message-----
> From: Eric W. Biederman [mailto:[email protected]]
> Sent: Monday, June 26, 2006 2:21 PM
> To: Miller, Mike (OS Dev)
> Cc: [email protected]; Maneesh Soni; Andrew Morton;
> [email protected]; [email protected];
> [email protected]; [email protected]
> Subject: Re: [Fastboot] [RFC] [PATCH 2/2] kdump: cciss driver
> initialization issue fix
>
> >> "Miller, Mike (OS Dev)" <[email protected]> writes:
> >>
> >> > Thanks Eric, that helps me understand. Section 8.2.2 of the
> >> open cciss
> >> > spec supports a reset message. Target 0x00 is the
> >> controller. We could
> >> > add this to the init routine to ensure the board is made
> sane again
> >> > but this would drastically increase init time under normal
> >> circumstances.
> >>
> >> Where does the init time penalty come from? How large is the init
> >> penalty? I suspect it is from waiting for the scsi disks
> to spin up.
> >> But I am just guessing in the dark.
> >
> > The penalty is in the firmware and self-test operations.
>
> Ok. Reasonable. Roughly long does that take? 1 millisecond? 1 second?
> 1 minute? 1 hour?
Sorry, roughly 30 to 40 seconds. Maybe longer if the controller thinks
there's something wrong with the disks. Typically the disks are always
spinning so that delay is not an issue.
>
> >> > And I suspect this is a hard reset, also. Not sure if that would
> >> > negatively impact kdump. If there were some condition we
> could test
> >> > against and perform the reset when that condition is met it
> >> would not
> >> > impact 99.9% of users.
> >>
> >> I am wondering if it is possible to look at the controller
> and see if
> >> it is in a bad state, (i.e. in some state besides just
> coming out of
> >> reset) and if so issue a reset. If this really is a long
> operation
> >> that would be the ideal way to handle it.
> >
> > It's not really in a bad state at this time, is it? Maybe some
> > commands hanging around.
>
> Not bad as in broken. But bad as in unexpected. If it is
> just a matter of outstanding commands we might even be able
> to just ask the adapter to cancel all of the at initialization time.
We can't detect unexpected but we can discard everything at init.
> >
> > I was informed of the crashboot command line parameter. I can
> > implement that as a test.
>
> Sounds like a start.
>
> >> Although it might simply be appropriate to handle commands
> completing
> >> you didn't start. I am not at all familiar with that particular
> >> piece of hardware so I can't make a good guess on what needs to
> >> happen there.
> >
> > Not sure about doing this.
>
> Well I would certainly print a warning.
>
> Eric
>
>
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