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SubjectRE: [Fastboot] [RFC] [PATCH 2/2] kdump: cciss driver initialization issue fix
Date
From
> -----Original Message-----
> From: Eric W. Biederman [mailto:ebiederm@xmission.com]
> Sent: Monday, June 26, 2006 12:52 PM
> To: Miller, Mike (OS Dev)
> Cc: vgoyal@in.ibm.com; Maneesh Soni; Andrew Morton;
> Neela.Kolli@engenio.com; linux-scsi@vger.kernel.org;
> fastboot@lists.osdl.org; linux-kernel@vger.kernel.org
> Subject: Re: [Fastboot] [RFC] [PATCH 2/2] kdump: cciss driver
> initialization issue fix
>
> "Miller, Mike (OS Dev)" <Mike.Miller@hp.com> 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.

>
> > 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.

>
> If the amount of time is really user noticeable and testing
> for it is impossible then it is probably time to talk kernel
> command line options.

I was informed of the crashboot command line parameter. I can implement
that as a test.

>
> 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.

mikem
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