From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: ahci: CAP_SSS and parallel scan Date: Fri, 07 May 2010 07:16:07 +0200 Message-ID: <4BE3A217.2030407@kernel.org> References: <4BE27C49.5090809@kernel.org> <4BE28C4F.9000903@linux.intel.com> <4BE2D5D6.1010705@kernel.org> <4BE3244A.7060607@teksavvy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from hera.kernel.org ([140.211.167.34]:45286 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752028Ab0EGFQg (ORCPT ); Fri, 7 May 2010 01:16:36 -0400 In-Reply-To: <4BE3244A.7060607@teksavvy.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Mark Lord Cc: Arjan van de Ven , Jeff Garzik , t.artem@mailcity.com, "linux-ide@vger.kernel.org" On 05/06/2010 10:19 PM, Mark Lord wrote: > On 06/05/10 03:49 PM, Jeff Garzik wrote: >> >>> Currently, there's no way to tell whether staggered spin up is needed >>> or drives are already spun up. > > Perhaps by issuing a "CHECK POWER MODE" command? > For many drives, a non-spinning drive is detectable from its IDENTIFY data. Heh, yeah, I wish it were like that. IIRC, there are two different staggered spin up scheme. The one implemented by CAP_SSS uses link init sequence as signal to spin up which means you don't even know whether there's a device attached before committing to spinning it up. Gotta love ATA. :-) -- tejun