Re: PMP SMART error recovery and failure code decoding help

[Marc MERLIN <marc@merlins.org>]

On Mon, Jan 17, 2011 at 02:26:23PM +0100, Tejun Heo wrote:
> Hello,

Hi (sorry that got cut out of my original message :) ).

> On Sun, Jan 16, 2011 at 08:39:50AM -0800, Marc MERLIN wrote:
> > Anyway, the problem happens with both drives that I manually spin down and
> > drives that spin down on their own. I think it's not actually a 'real',
> > error but more an issue where drives cannot answer some SMART error when
> > they are spun down.
> 
> It could be that the drives need to spin up to answer the smart
> command and the timeout on the smart commands is a bit too short for
> that to happen.  Forcing a disk access before issuing the smart
> command could work around the problem.
 
Right, although the idea is of course to keep the drives spun down :)
I haven't been able to find which SMART call is causing those errors yet.
Does cmd b0/d8:00:00:4f:c2/00:00:00:00:00/00 translate to anything useful?

> > That said, is it normal/expected for the PMP code to do a full bus reset
> > because of a SMART command that couldn't go through?
> 
> Yeah, after a timeout, the driver doesn't know what state the
> controller / PMP / devices are in, so it's kind of forced to do full
> reset.

Fair enough. I guess it's one of the downsides of PMP.

Thanks for the answer,
Marc
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