From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH 1/1] AHCI: disabled FBS prior to issuing software reset Date: Sat, 28 Sep 2013 07:49:50 -0400 Message-ID: <20130928114950.GA2620@htj.dyndns.org> References: <1380366816-16221-1-git-send-email-yxlraid@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-qc0-f180.google.com ([209.85.216.180]:34506 "EHLO mail-qc0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751654Ab3I1Ltz (ORCPT ); Sat, 28 Sep 2013 07:49:55 -0400 Content-Disposition: inline In-Reply-To: <1380366816-16221-1-git-send-email-yxlraid@gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Xiangliang Yu Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Hello, On Sat, Sep 28, 2013 at 07:13:36PM +0800, Xiangliang Yu wrote: > If device is attached to port multiplier, the detection process > look like this: > ahci_hardreset(link, class, deadline) > if (class == ATA_DEV_PMP) { > sata_pmp_attach(dev) /* will enable FBS */ > sata_pmp_init_links(ap, nr_ports); > ata_for_each_link(link, ap, EDGE) { > sata_std_hardreset(link, class, deadline); > if (link_is_online) > ahci_softreset(link, class, deadline); > } > } > But, according to chapter 9.3.9 in AHCI spec: Prior to issuing software reset, > software shall clear PxCMD.ST to '0' and then clear PxFBS.EN to '0'. How was this tested? Do you observe any behavior difference? At this point, we are not using SRST on PMP ports anyway, so I can't see how this would make any difference. Thanks. -- tejun