Re: aic7xxx sets CDR offline, how to reset?

[Doug Ledford <dledford@redhat.com>]

On Wed, Sep 04, 2002 at 12:37:37PM +0200, Andries Brouwer wrote:
> 
> The scsi error recovery has many bad properties, but one is its slowness.

This does not have to be this way.  It is a solvable problem.

> Once it gets triggered on a machine with SCSI disks it is common to
> have a dead system for several minutes.

Yes, well, this too is solvable.  It, in fact, reminds me that one of the 
things I think needs added to the scsi host settings is a default timeout 
value for typical devices.  Something like adding a default_timeout value 
to each Scsi_Device struct and allowing the scsi driver to modify the 
value during the slave_attach() call.  Then we can put the default timeout 
on non-intelligent controllers to something sane while things like 
MegaRAID controllers can keep their sky high timeout values.

> I have not yet met a situation
> in which rebooting was not preferable above scsi error recovery,
> especially since the attempt to recover often fails.

This, too, is solvable.  It just requires that the scsi subsystem start 
paying attention to *how* things fail and making the error handling code 
smart enough to know when to retry things and when to just fail.

-- 
  Doug Ledford <dledford@redhat.com>     919-754-3700 x44233
         Red Hat, Inc. 
         1801 Varsity Dr.
         Raleigh, NC 27606