From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 14 Mar 2003 15:18:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 14 Mar 2003 15:18:13 -0500 Received: from h-64-105-35-119.SNVACAID.covad.net ([64.105.35.119]:8328 "EHLO freya.yggdrasil.com") by vger.kernel.org with ESMTP id ; Fri, 14 Mar 2003 15:18:12 -0500 From: "Adam J. Richter" Date: Fri, 14 Mar 2003 12:28:47 -0800 Message-Id: <200303142028.MAA02437@adam.yggdrasil.com> To: EdV@macrolink.com Subject: RE: devfs + PCI serial card = no extra serial ports Cc: driver@jpl.nasa.gov, dwmw2@infradead.org, linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 14 Mar 2003 at 11:49:54, Ed Vance wrote: >The largest gotcha that I am aware of for the PCI/setserial command >combination is the inability to automatically "follow" the card when >its address changes due to adding or removing an unrelated PCI device. >Even so, the system is unlikely to crash because the driver checks the >LSR register for impossible values and cuts off access when the UART >is not present. I would expect that setserial should only be used in cases where this information is not reliably determinable by the kernel through hardware device ID facilities, such as what we have in PCI, USB, etc. If that is not already the case, it should be straightforward to fix in the kernel sources, which seemed to be most of what the "3 Serial issues up for discussion" thread was about (thanks for the pointer). There was tangential mention in that thread of a "/proc/serialdev" interface, but nobody really identified any real benefit to it over the existing "uart: unknown" system. Anyhow, my primary point in this discussion is just to say that, as far as I can tell, devfs does not impede the serial driver from doing what Ted Ts'o seemed to be describing. Adam J. Richter __ ______________ 575 Oroville Road adam@yggdrasil.com \ / Milpitas, California 95035 +1 408 309-6081 | g g d r a s i l United States of America "Free Software For The Rest Of Us."