----- Original Message -----
From: <[EMAIL PROTECTED]>
To: Eric Youngdale <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Monday, December 13, 1999 10:57 AM
Subject: Re: How do I invoke a re-probe from kernel space?


> Hi Eric,
>
> you wrote:
> >    My guess is that the problem is that when you do an
> > add-single-device that it calls down to the low-level driver to select
> the
> > queue depth again.  The problem is (as the comment describes) that the
> > low-level drivers may not expect being called to do this task a second
> > time.
>
> So, it appears to me that
> a) the problem is in the aic7xxx low-level driver.

    Not really.  The function to set the queue depth was never designed for
this purpose.  Thus the driver would have reason to be surprised by being
called a second time.   In such a case there is kind of a grey area as to
where the problem might be.

    Realistically, I suspect that the easiest fix is to get the aic7xxx
driver to tolerate being called again, assuming that this is where the
problem actually lies.

> b) the problem will not be cured in the next 2.3 releases.

    Correct.

> Allow me to repeat my previous questions:
> 1. Has anybody else experienced this loss of tagged command
>    queueing on "add-single-device"?
> 2. Is anybody working on a solution, especially for the aic7xxx driver?
>
> The "add-single-device" is **VERY** handy. I want to use it to be able to
> switch my SCSI DAT tape on and off without the need to reboot. But if I
> lose
> the queue depth for my SCSI disks, I fear the perfomance penalty... :-(
>
>
> Mit freundlichen Gruessen / best regards
>
> Michael Kwasigroch
> FaxPlus/Open Development
> ________________________________________
>
> eMail:        [EMAIL PROTECTED]
>
> INTERCOPE GmbH, Hamburg, Bebelallee 72
>
>


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