Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751117AbWERAgf (ORCPT ); Wed, 17 May 2006 20:36:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751125AbWERAgf (ORCPT ); Wed, 17 May 2006 20:36:35 -0400 Received: from mga01.intel.com ([192.55.52.88]:51865 "EHLO fmsmga101-1.fm.intel.com") by vger.kernel.org with ESMTP id S1751117AbWERAge convert rfc822-to-8bit (ORCPT ); Wed, 17 May 2006 20:36:34 -0400 X-IronPort-AV: i="4.05,139,1146466800"; d="scan'208"; a="38894888:sNHT16630824168" X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Subject: RE: [RFT] major libata update Date: Wed, 17 May 2006 20:36:12 -0400 Message-ID: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [RFT] major libata update Thread-Index: AcZ6DITV2vvp3U/jS0e592rCAWCyZwABNpgg From: "Brown, Len" To: "Jeff Garzik" , "Linus Torvalds" Cc: "OGAWA Hirofumi" , "Avuton Olrich" , , , X-OriginalArrivalTime: 18 May 2006 00:36:13.0781 (UTC) FILETIME=[112DA850:01C67A13] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1413 Lines: 36 >Many BIOS ACPI tables from years ago simply _assumed_ that you have >hardcoded irq 14/15, even... Their irq descriptors for 14/15 would be >absent or completely non-functional. > >Or maybe its the $pirq table I'm recalling. One of the two, anyway. For x86, the ACPI interrupt configuration process is to identity-map the IOAPIC entries below 16 1:1 PIC:IOAPIC, unless there are interrupt source overrides (such as commonly done to swizzle IRQ0 from a different pin) This makes legacy-mode ATA happy. Hard code ATA to 14/15 and off you go. But there is a gray area where the ATA controller registers as a PCI device, but Linux goes off and looks in the ACPI PRT for that PCI-dev and finds no entry. So if you didn't have the hard-coded 14/15, you'd be dead. Then there are cases where the PRT specifies something _other_ than 14/15 for ATA, and in that cases the hard-coded default is the wrong thing to do; and the workaround is to use BIOS SETUP options to be sure that ATA is set up in legacy mode. I suspect Linux could be smarter here. The 14/15 should be the backup default for when the tables don't give us anything else; not the only option. -Len - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/