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Date: Tue, 12 Jun 2007 08:43:19 -0700
From: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
To: Jeff Garzik <jeff@garzik.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>, Tejun Heo <htejun@gmail.com>,
       james.bottomley@steeleye.com, linux-ide@vger.kernel.org,
       linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
       Pavel Machek <pavel@ucw.cz>, Jens Axboe <jens.axboe@oracle.com>
Subject: Re: [patch 0/3] AHCI Link Power Management
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On Tue, 12 Jun 2007 00:43:12 -0400
Jeff Garzik <jeff@garzik.org> wrote:

> We will do AHCI link PM -- presuming that I can be convinced that it 
> does not repeatedly park the hard drive heads, or something similarly 
> annoying on PATA<->SATA bridges and similar setups.
> 
> IF it works as advertised -- a big if considering all the AHCI silicon 
> implementations out there -- we definitely want to use it.
> 
> 	Jeff
> 

I understand that this is a concern of yours based on some experience you
had with earlier controllers.  In general, this behavior would be considered
incorrect - link power management should not translate to disk parking, even
on PATA->SATA brigdes, and if it does, then that's completely broken.  That 
said, I would believe you if you said broken hardware exists, and when you 
get specific examples of it, you can add it to the blacklist for this feature.