From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: PATCH: Explain the PCI bus test we do in IDE Date: Fri, 21 Oct 2005 14:14:58 +0100 Message-ID: <1129900498.26367.27.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from [81.2.110.250] ([81.2.110.250]:48311 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id S964926AbVJUMqP (ORCPT ); Fri, 21 Oct 2005 08:46:15 -0400 Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, akpm@osdl.org Matthew Wilcox asked that this got a comment explaining why it is done so here it is. Signed-off-by: Alan Cox diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.14-rc4-mm1/include/asm-i386/ide.h linux-2.6.14-rc4-mm1/include/asm-i386/ide.h --- linux.vanilla-2.6.14-rc4-mm1/include/asm-i386/ide.h 2005-10-20 16:10:12.000000000 +0100 +++ linux-2.6.14-rc4-mm1/include/asm-i386/ide.h 2005-10-20 16:37:20.000000000 +0100 @@ -41,6 +41,12 @@ static __inline__ unsigned long ide_default_io_base(int index) { + /* + * If PCI is present then it is not safe to poke around + * the other legacy IDE ports. Only 0x1f0 and 0x170 are + * defined compatibility mode ports for PCI. A user can + * override this using ide= but we must default safe. + */ if (pci_find_device(PCI_ANY_ID, PCI_ANY_ID, NULL) == NULL) { switch(index) { case 2: return 0x1e8;