From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH RFC] ahci: implement handoff quirk Date: Sat, 11 Apr 2009 12:54:51 -0400 Message-ID: <49E0CB5B.3070807@garzik.org> References: <485882FE.1060409@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:56235 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753280AbZDKQy4 (ORCPT ); Sat, 11 Apr 2009 12:54:56 -0400 In-Reply-To: <485882FE.1060409@kernel.org> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: IDE/ATA development list , "Zhao, Richard" , shane.huang@amd.com 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 We probably need to do this... it's not a controller requirement but a BIOS one, so in theory even an existing, deployed AHCI 1.2 platform could suddenly require BIOS/OS handoff, if a BIOS update suddenly starts doing new and weird stuff in SMI. Note that we need to do BIOS/OS handoff upon resume as well as at boot time. Jeff