From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tejun Heo <tj@kernel.org>
Subject: Re: 'Device not ready' issue on mpt2sas since 3.1.10
Date: Mon, 23 Jul 2012 08:26:19 -0700
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To: Matthias Prager <linux@matthiasprager.de>
Cc: Robert Trace <maillist@farcaster.org>, linux-scsi@vger.kernel.org, Jens Axboe <jaxboe@fusionio.com>, Eric Moore <Eric.Moore@lsi.com>, "James E.J. Bottomley" <JBottomley@parallels.com>, Alan <alan@lxorguk.ukuu.org.uk>, "Darrick J. Wong" <djwong@us.ibm.com>, Matthias Prager <linux@matthiaspragers.de>

Hello,

On Mon, Jul 23, 2012 at 01:14:00AM +0200, Matthias Prager wrote:
> as it turns out my workaround (setting allow_restart=1) isn't all that
> useful after all. There are no more i/o errors because the drive just
> never goes to standby mode anymore (at least 'hdparm -y /dev/sda' does
> not seem to have any effect anymore). I don't really understand why - do
> sas drives ever get to standby mode? (they have allow_restart=1 set by
> default) And is this desired or expected behavior for sata disk on sas
> controllers?
> 
> For the moment the only way for me to have my sata drives sleeping
> without i/o errors is to revert your original commit
> (85ef06d1d252f6a2e73b678591ab71caad4667bb - tested with kernels 3.1.10,
> 3.4.4, 3.4.5, 3.4.6 and 3.5.0)

Hmmm... I think we definitely need help from mpt people.  Ping, guys.

> P.S. I hope I'm not getting on everybody's nerves here (especially yours
> Tejun)

Not at all. :)

Thanks.

-- 
tejun