From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965056AbVHPBIe (ORCPT ); Mon, 15 Aug 2005 21:08:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965059AbVHPBIe (ORCPT ); Mon, 15 Aug 2005 21:08:34 -0400 Received: from stat16.steeleye.com ([209.192.50.48]:55249 "EHLO hancock.sc.steeleye.com") by vger.kernel.org with ESMTP id S965056AbVHPBId (ORCPT ); Mon, 15 Aug 2005 21:08:33 -0400 Subject: RE: [PATCH] add transport class symlink to device object From: James Bottomley To: James.Smart@Emulex.Com Cc: matthew@wil.cx, Greg KH , Andrew Morton , SCSI Mailing List , Linux Kernel , Alan Cox , Russell King In-Reply-To: <9BB4DECD4CFE6D43AA8EA8D768ED51C201AD39@xbl3.ma.emulex.com> References: <9BB4DECD4CFE6D43AA8EA8D768ED51C201AD39@xbl3.ma.emulex.com> Content-Type: text/plain Date: Mon, 15 Aug 2005 20:08:14 -0500 Message-Id: <1124154494.5089.86.camel@mulgrave> Mime-Version: 1.0 X-Mailer: Evolution 2.0.4 (2.0.4-6) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2005-08-15 at 20:52 -0400, James.Smart@Emulex.Com wrote: > What is "0000:00:04:0" in this case ? The "device" is not a serial > port, which is what the ttyXX back link would lead you to believe. > Thus, it's a serial port multiplexer that supports up to N ports, > right ? and wouldn't the more correct representation have been to > enumerate a device for each serial port ? (e.g. 0000:00:04.0/line0, > 0000:00:04.0/line1, or similar) It's PCI segment 0, bus 0, slot 4, function 0, which is apparently a 3 port serial card (probably the GSP function of a pa8800?) > Think if SCSI used this same style of representation. For example, > if there was no scsi target device entity, but class entities did > exist and they just pointed back to the scsi host device entry. Yes, it's theoretically possible to have had SCSI do this. We didn't do it at the time because class_devices didn't exist when the SCSI tree was first put together. It would, however, have rather put the mockers on doing transport classes since class devices can't point at other class devices. > My vote is to make the multiplexor instantiate each serial line > as a separate device. That's a choice that's up to the maintainer of the serial driver ... James