From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756823AbXIUKak (ORCPT ); Fri, 21 Sep 2007 06:30:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752897AbXIUKad (ORCPT ); Fri, 21 Sep 2007 06:30:33 -0400 Received: from brick.kernel.dk ([87.55.233.238]:24478 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751151AbXIUKac (ORCPT ); Fri, 21 Sep 2007 06:30:32 -0400 Date: Fri, 21 Sep 2007 12:31:20 +0200 From: Jens Axboe To: Peer Chen Cc: linux-kernel , jeff , akpm , linux-ide Subject: Re: [PATCH] ahci: enable GHC.AE bit before set GHC.HR Message-ID: <20070921103120.GK2367@kernel.dk> References: <200709211327569648280@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <200709211327569648280@gmail.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 21 2007, Peer Chen wrote: > According to the description of section 5.2.2.1 and 10.1.2 of AHCI specification rev1_1/rev1_2, GHC.HR shall only be set to ¡®1¡¯ > by software when GHC.AE is set to ¡®1¡¯. > > Signed-off-by: Peer Chen > --- > --- linux-2.6.23-rc7/drivers/ata/ahci.c.orig 2007-09-20 11:01:55.000000000 -0400 > +++ linux-2.6.23-rc7/drivers/ata/ahci.c 2007-09-20 11:07:31.000000000 -0400 > @@ -834,6 +834,10 @@ static int ahci_reset_controller(struct > void __iomem *mmio = host->iomap[AHCI_PCI_BAR]; > u32 tmp; > > + /* turn on AHCI mode before controller reset*/ > + writel(HOST_AHCI_EN, mmio + HOST_CTL); > + (void) readl(mmio + HOST_CTL); /* flush */ > + > /* global controller reset */ > tmp = readl(mmio + HOST_CTL); > if ((tmp & HOST_RESET) == 0) { I appreciate the readl() flushes, but in this particular case we end up reading the exact offset again below. -- Jens Axboe