From: Simon Farnsworth <simon.farnsworth@onelan.co.uk>
To: Tejun Heo <htejun@gmail.com>
Cc: linux-ide@vger.kernel.org
Subject: Re: Freeze after disabling write cache with hdparm -W0 /dev/sda
Date: Wed, 11 Jul 2007 09:54:09 +0100 [thread overview]
Message-ID: <46949AB1.80705@onelan.co.uk> (raw)
In-Reply-To: <469496A4.7070902@gmail.com>
Tejun Heo wrote:
> Simon Farnsworth wrote:
>> Just a thought; is it possible to trigger libata EH from userspace? If
>> so, we could write a small utility to disable write cache, then force EH
>> to detect the change.
>
> That's automatically done. libata snoops cache on/off and triggers
> revalidation but you can request manual rescan by echoing "- - -" to
> /sys/class/scsi_host/hostX/scan.
>
Would it be worth changing our code to do "hdparm -W1 /dev/sda && hdparm
-W0 /dev/sda", or would this not show anything. The lack of revalidation
on some drives is what's worrying me a little here.
--
Simon Farnsworth
next prev parent reply other threads:[~2007-07-11 8:54 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-10 10:15 Freeze after disabling write cache with hdparm -W0 /dev/sda Simon Farnsworth
2007-07-11 5:11 ` Tejun Heo
2007-07-11 8:31 ` Simon Farnsworth
2007-07-11 8:36 ` Tejun Heo
2007-07-11 8:54 ` Simon Farnsworth [this message]
2007-07-11 8:57 ` Tejun Heo
2007-07-11 12:25 ` Simon Farnsworth
2007-07-13 7:45 ` Tejun Heo
2007-07-17 8:57 ` Simon Farnsworth
2007-07-11 18:46 ` Mark Lord
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