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From: ebiederm@xmission.com (Eric W. Biederman)
To: vgoyal@in.ibm.com
Cc: Maneesh Soni <maneesh@in.ibm.com>, Andrew Morton <akpm@osdl.org>,
       Neela.Kolli@engenio.com, linux-scsi@vger.kernel.org, mike.miller@hp.com,
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Subject: Re: [Fastboot] [RFC] [PATCH 2/2] kdump: cciss driver initialization issue fix
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Date: Mon, 26 Jun 2006 11:39:21 -0600
In-Reply-To: <20060626171659.GG8985@in.ibm.com> (Vivek Goyal's message of
	"Mon, 26 Jun 2006 13:16:59 -0400")
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Vivek Goyal <vgoyal@in.ibm.com> writes:

> On Mon, Jun 26, 2006 at 10:00:55AM -0600, Eric W. Biederman wrote:

> I think it does hurt.
>
> - I have seen the case of MPT fusion drvier. It takes significantly more
>   time to come up if we choose to reset the device during initialization.
>   One of the reasons that we wait in a tight loop for the controller to 
>   come up after a reset message.
>
> - Long back we fixed ips driver and I remember that the maintainer had
>   a similar issue with the reset of device. He did not want to reset the
>   device in normal boot because otherwise it took significantly longer
>   for the driver to initialize.
>
> - Just now Mike also confirmed that resetting the device definitely
>   hurts in terms of time.

In the general case resets are trivial operations.  In scsi land 
things are different.  So a solution appropriate to that domain may
be appropriate.

Eric