"Robin T. Miller" wrote:
> Regarding "timeout values back down to about 8 seconds"...
>
> I think you'll find some devices after exhausting it's retries w/ECC,
> and perhaps performing Automatic Read/Write Allocation for bad blocks, your 8
> second timeout will be exceeded, leading to false errors. Of course tapes
> and medium changers require much longer command timeouts. Timeouts should
> be controlled by the device driver generating the request (IMHO).
This is as much a gray area as anything. Consider this, only the device
driver knows if the device that was found is real or logical. That can make a
big difference in timeout values. At the same time, you don't want the device
drivers to be responsible for knowing the name and model of each external SCSI
device that is actually a raid device. So maybe what we should be doing here
is allowing the Scsi_Host_Template to include a *default* timeout value for
SCSI disks. Then, the high level drivers can modify that number based on
extenuating circumstances. Maybe sd.c would take the max of the default
number and the value for the device based upon a vendor/model lookup that
would allow us to create some external raid device whitelist that had modified
timeout values for those raid devices.
> Also, I think you need to honor the device timeout setup, since your
> driver does not know if an external RAID box is attached.
And I don't want it to know, so the sd.c code should be allowed to override my
default value for external raid controllers. However, I still want regular
disks to get reasonable timeouts, hence the default value. The st.c and sr.c
code could likewise override the default value as a regular matter of course.
> You may also find there are other commands, such as Test Unit Ready,
> which require longer timeouts for RAID boxes which do transparent controller
> failover. Replacing all hardcoded timeouts with variables would be great!
>
> Kind Regards,
> Robin
>
> >
> > --
> >
> > Doug Ledford <[EMAIL PROTECTED]> http://people.redhat.com/dledford
> > Please check my web site for aic7xxx updates/answers before
> > e-mailing me about problems
> >
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--
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