From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: Re: [ACPI] Re: RFC: ACPI/scsi/libata integration and hotswap Date: Thu, 08 Dec 2005 14:30:57 +0000 Message-ID: <1134052257.17102.13.camel@localhost.localdomain> References: <20051208030242.GA19923@srcf.ucam.org> <20051208091542.GA9538@infradead.org> <20051208132657.GA21529@srcf.ucam.org> <20051208133308.GA13267@infradead.org> <20051208133945.GA21633@srcf.ucam.org> <20051208135225.GA13122@havoc.gtf.org> <1134050863.17102.5.camel@localhost.localdomain> <43983FC6.6050108@pobox.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <43983FC6.6050108@pobox.com> Sender: linux-kernel-owner@vger.kernel.org To: Jeff Garzik Cc: Matthew Garrett , Christoph Hellwig , 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 List-Id: linux-ide@vger.kernel.org On Iau, 2005-12-08 at 09:14 -0500, Jeff Garzik wrote: > These are only for PATA. We don't care about _GTM/_STM on SATA. Even your piix driver supports PATA. Put the foaming (justified ;)) hatred for ACPI aside for a moment and take a look at the real world as it unfortunately is right now. > Further, SATA completely resets and re-initializes the device as if from > a hardware reset (except on ata_piix, which doesn't support COMRESET, > and PATA). This makes _GTF uninteresting, as well. You don't know what the sequences the resume method is concerned about actually are. > suspend/resume works just fine with Jens' out-of-tree patch. Only on some systems. > > If you don't run the resume methods your disk subsystem status after a > > resume is simply undefined and unsafe. > > I initialize the hardware to a defined state. Sure, but sometimes the *wrong* defined state. The BIOS ACPI methods include things like unlocking drive passwords on restore with some systems. You don't handle that at all. Having said that I still think ACPI awareness doesn't belong in libata or scsi because we'd then have awareness of every pm scheme in the wrong layer and a dozen pm systems all with scsi hooks. Gak... SCSI/libata can go easily from ata channel to pci device to device. The rest of the logic belongs outside of scsi/libata. Alan