Re: [PATCH] libata: Handle drives that require a spin-up command before first access

[Tejun Heo <htejun@gmail.com>]

Mark Lord wrote:
> I'm resending this now that reverse-DNS has been fixed on
> our out-going mail server.
> 
> Jeff, this would be a very good thing to queue up for 2.6.22,
> as otherwise drives become permanent paperweights when
> the "power-up-in-standby" feature is turned on.
> 
> Cheers
> 
> 
> -------- Original Message --------
> Subject: [PATCH] libata: Handle drives that require a spin-up command
> before first access
> Date: Tue, 17 Apr 2007 18:26:07 -0400
> From: Mark Lord <liml@rtr.ca>
> To: Jeff Garzik <jgarzik@pobox.com>,  IDE/ATA development list
> <linux-ide@vger.kernel.org>
> CC: Tejun Heo <htejun@gmail.com>, Alan Cox <alan@redhat.com>
> 
> 
> (S)ATA drives can be configured for "power-up in standby",
> a mode whereby a specific "spin up now!" command is required
> before the first media access.
> 
> Currently, a drive with this feature enabled can not be used at all
> with libata, and once in this mode, the drive becomes a doorstop.
> 
> The older drivers/ide subsystem at least enumerates the drive,
> so that it can be woken up after the fact from a userspace HDIO_*
> command, but not libata.
> 
> This patch adds support to libata for the "power-up in standby"
> mode where a "spin up now!" command (SET_FEATURES) is needed.
> With this, libata will recognize such drives, spin them up,
> and then re-IDENTIFY them if necessary to get a full/complete
> set of drive features data.
> 
> Drives in this state are determined by looking for
> special values in id[2], as documented in the current ATA specs.
> 
> Signed-off-by: Mark Lord <mlord@pobox.com>

Acked-by: Tejun Heo <htejun@gmail.com>

-- 
tejun