From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH 1/1] libata: ahci_start_engine compliant to AHCI spec Date: Sat, 23 Apr 2011 16:40:44 +0200 Message-ID: References: <1303541890-14528-1-git-send-email-jipeng2005@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Return-path: In-Reply-To: <1303541890-14528-1-git-send-email-jipeng2005@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Jian Peng Cc: Jeff Garzik , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-ide@vger.kernel.org On Sat, Apr 23, 2011 at 8:58 AM, Jian Peng wrote: > At the end of section 10.1 of AHCI spec (rev 1.3), it states > > Software shall not set PxCMD.ST to 1 until it is determined that > a functoinal device is present on the port as determined by > PxTFD.STS.BSY=0, PxTFD.STS.DRQ=0 and PxSSTS.DET=3h > > Even though most AHCI host controller works without this check, > specific controller will fail under this condition. > > Signed-off-by: Jian Peng Acked-by: Tejun Heo Thanks. -- tejun