--- Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> > I think that "scanning" is a special process which should involve
> > the minimum of error handling, by either ignoring errors and trying
> > to connect to the device anyway, or on the first error, give up
> > the device. Which policy would one follow depends on the transport.
>
> No, that's not feasible. We can't just ignore errors, and we do have to
> cope with them. Scanning is a particular vulnerable time, since it
> involves sending commands that don't occur most of the time during normal
> operation.
Your reasoning is correct, but your conclusion is not.
Exactly, scanning is a "particularly vulnerable time" and this is why
we do not want the full I_T nexus error recovery. At scanning time
we're just "probing" here and there.
> > If the latter, you need to blacklist the device as not supporting
> > TUR. Then on any error, like you pulling the cable during scanning,
> > the scanning process will give up and all will be well.
>
> You can't blacklist devices you don't know about. The kernel should work
> regardless.
Hmm, I thought there was a black listing somewhere in scsi, maybe
/proc/scsi/device_info?
So then you do scheme #1 as I described: ignore as much as possible and try
to establish an I_T nexus and _then_ try to poke around with the device.
Luben
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