From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Hancock Subject: Re: [PATCH RFC] ahci: implement handoff quirk Date: Thu, 17 Dec 2009 21:54:30 -0600 Message-ID: <4B2AFCF6.5030602@gmail.com> References: <485882FE.1060409@kernel.org> <4B29D0FA.6060805@garzik.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-yx0-f187.google.com ([209.85.210.187]:61618 "EHLO mail-yx0-f187.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756853AbZLRDyd (ORCPT ); Thu, 17 Dec 2009 22:54:33 -0500 Received: by yxe17 with SMTP id 17so2580132yxe.33 for ; Thu, 17 Dec 2009 19:54:32 -0800 (PST) In-Reply-To: <4B29D0FA.6060805@garzik.org> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Jeff Garzik Cc: Tejun Heo , IDE/ATA development list , "Zhao, Richard" , shane.huang@amd.com On 12/17/2009 12:34 AM, Jeff Garzik wrote: > On 06/17/2008 11:37 PM, Tejun Heo wrote: >> ahci 1.2 has an exciting! new feature called BIOS/OS handoff which >> basically is there to allow BIOS to keep tinkering with the controller >> even after OS starts executing. I have no idea what this is useful >> for but it's there and we need to do it. >> >> This patch implements the handoff as FIXUP_HEADER as the controller >> needs to be claimed before the OS changes any configuration including >> IRQ routing. >> >> I'm yet to see any controller which actually requires this, so it's >> not for inclusion yet. Maybe keep this in a separate branch? >> >> RFC, DON'T COMMIT >> --- >> drivers/pci/quirks.c | 109 >> +++++++++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 109 insertions(+) > > Looking through old emails... did AMD ever confirm the usefulness of > this patch? Is it actually needed in the field? I'm guessing the silence > implies "No"... :) Well, we only implemented the feature bit displaying for the BOH "capability" recently, so I guess we wouldn't likely have seen it if something did advertise it. However, it's true I don't know why any sane BIOS would want to do this. Can't hurt to have the support, however..