From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964873AbVLITyw (ORCPT ); Fri, 9 Dec 2005 14:54:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932423AbVLITyw (ORCPT ); Fri, 9 Dec 2005 14:54:52 -0500 Received: from atlrel6.hp.com ([156.153.255.205]:49318 "EHLO atlrel6.hp.com") by vger.kernel.org with ESMTP id S932424AbVLITyv (ORCPT ); Fri, 9 Dec 2005 14:54:51 -0500 From: Bjorn Helgaas To: "Jason Dravet" Subject: Re: wrong number of serial port detected Date: Fri, 9 Dec 2005 12:54:44 -0700 User-Agent: KMail/1.8.2 Cc: rmk+lkml@arm.linux.org.uk, linux-kernel@vger.kernel.org References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200512091254.44770.bjorn.helgaas@hp.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Friday 09 December 2005 7:37 am, Jason Dravet wrote: > The question I have > is with all of this plug and play stuff in our PCs shouldn't it be possible > to get the correct number of ports, ask the bios or the pci bus or > something? Yes. ACPI (or even PNPBIOS) should tell us about all the "legacy" ports, and PCI or other bus enumeration should tell us about all the rest. So in theory, if we have some flavor of PNP, we should be able to ignore all the compiled-in stuff in SERIAL_PORT_DFNS, which is what leads to the duplicate port detection. I've considered doing that (and ia64 already does it), but it would almost certainly break systems because of BIOS bugs, so I'm not sure it's worth the risk. Having all the extra /dev/ttyS entries is a little different problem. That is basically so "setserial /dev/ttySx" can be used to work around the fact that the serial driver doesn't know about all existing devices. If it did, setserial should be superfluous. Maybe there'd be a way to implement that functionality via sysfs and get rid of the extra /dev/ttyS entries. That'd be kind of cool.