From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 20 Oct 2001 13:04:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 20 Oct 2001 13:04:10 -0400 Received: from mta6.snfc21.pbi.net ([206.13.28.240]:27280 "EHLO snfc21.pbi.net") by vger.kernel.org with ESMTP id ; Sat, 20 Oct 2001 13:04:00 -0400 Date: Sat, 20 Oct 2001 10:03:17 -0700 From: David Brownell Subject: Re: RFC: New Driver Model for 2.5 To: Patrick Mochel Cc: lkml Message-id: <0f2f01c15989$1de93960$6800000a@brownell.org> MIME-version: 1.0 X-MIMEOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 X-Mailer: Microsoft Outlook Express 5.50.4133.2400 Content-type: text/plain; charset=iso-8859-1 Content-transfer-encoding: 7BIT X-Priority: 3 X-MSMail-priority: Normal In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org There seems to be a lot of agreement that having some explicit representation of the device tree will help do the power management better. That's something USB has so far not done; there's no current hook from the host controller drivers (HCDs) to power manage devices. (But then, there's no HCD layer yet either. Each HCD duplicates a lot of code, though there's work afoot to change that.) It might be appropriate to have, for example, the USB portions of the device tree handle hub parent/child style relationships. Hubs can't be resumed after their children, and so on. Likewise it's no good telling devices they should attempt remote wakeups unless all the hubs they are connected to can wake up their parent devices, too; no bus-powered hubs can be in that part of the tree. And better standards for device naming and identification are IMO good ... that'll improve diagnostics, and with a bit of care we can finally have reasonably "stable" names. Again, with USB the hub parent/child relationships are more stable than the bus addresses that get assigned; they can be used to distinguish the numerous devices that don't have serial numbers (or for which the serial numbers aren't really unique). - Dave