From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH] libata_acpi: A different strategy for using ACPI information Date: Wed, 04 Jul 2007 12:49:19 +0900 Message-ID: <468B18BF.6040207@gmail.com> References: <20070703155417.11d81c75@the-village.bc.nu> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from py-out-1112.google.com ([64.233.166.178]:10271 "EHLO py-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755302AbXGDDtZ (ORCPT ); Tue, 3 Jul 2007 23:49:25 -0400 Received: by py-out-1112.google.com with SMTP id u77so3619585pyb for ; Tue, 03 Jul 2007 20:49:24 -0700 (PDT) In-Reply-To: <20070703155417.11d81c75@the-village.bc.nu> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cox Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, jeff@garzik.org Alan Cox wrote: > Lots of BIOSen simply return the BIOS set modes via the ACPI methods and > pass back the values you give it across suspend/resume. Thus instead of > trying to do clever stuff with this data we instead use it as a way to > take a sneak peak at cable type information when viable. This should help > us catch more of the laptops that do weird stuff, the VIA SATA bridges > and the totally horked Nvidia cable handling. > > For now its only used by the VIA and AMD/NV driver until we get a better > idea of whether this is a sensible idea or not. > > Opinions ? If you don't do _STM first, it basically boils down to reading BIOS setting during boot. Over suspend/resume cycle, the values are preserved by libata-acpi. At this point, I think honoring the BIOS setting is the right thing to do. It just took us too long and I'm not too sure about using ACPI for this. It's generic so it's certainly better in some aspect. It's just a bit obfuscating, IMHO. -- tejun