From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: Re: RFC: ACPI/scsi/libata integration and hotswap Date: Fri, 9 Dec 2005 12:11:25 +0000 Message-ID: <20051209121124.GA25974@srcf.ucam.org> References: <20051208133945.GA21633@srcf.ucam.org> <1134050498.17102.2.camel@localhost.localdomain> <20051208141811.GB21715@srcf.ucam.org> <1134052433.17102.17.camel@localhost.localdomain> <20051208145257.GB21946@srcf.ucam.org> <20051208171901.GA22451@srcf.ucam.org> <20051209114246.GB16945@infradead.org> <20051209114944.GA1068@havoc.gtf.org> <20051209115235.GB25771@srcf.ucam.org> <43997171.9060105@pobox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from cavan.codon.org.uk ([217.147.92.49]:60628 "EHLO vavatch.codon.org.uk") by vger.kernel.org with ESMTP id S932254AbVLIMLs (ORCPT ); Fri, 9 Dec 2005 07:11:48 -0500 Content-Disposition: inline In-Reply-To: <43997171.9060105@pobox.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Jeff Garzik Cc: Christoph Hellwig , Alan Cox , randy_d_dunlap@linux.intel.com, linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, acpi-devel@lists.sourceforge.net On Fri, Dec 09, 2005 at 06:58:41AM -0500, Jeff Garzik wrote: > If this is for hotswap, as I noted, libata doesn't need this at all. > > If the hardware supports it, then libata will support it directly. > There is no ACPI-specific magic, because ACPI does nothing but talk to > the same hardware libata is talking to. If libata knows how to talk to the random hardware attached to a Dell laptop hotswap bay, I'll be amazed. Ejecting the drive generates a system management interrupt, which then causes the ACPI code to check a register in a block of machine-specific registers and generate an ACPI notification. As far as I can tell, the controller has no say in the matter at all - the Intel specs seem to suggest that ICH6 doesn't generate a hotswap interrupt unless you're using AHCI (which this hardware doesn't). So, as far as I can tell, there /is/ ACPI-specific magic on current-generation hardware. If we're lucky, they'll move to AHCI in future and implement things properly there - but I wouldn't count on it. -- Matthew Garrett | mjg59@srcf.ucam.org