Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757502Ab2JDUsa (ORCPT ); Thu, 4 Oct 2012 16:48:30 -0400 Received: from mail-ia0-f174.google.com ([209.85.210.174]:37907 "EHLO mail-ia0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757355Ab2JDUsS (ORCPT ); Thu, 4 Oct 2012 16:48:18 -0400 MIME-Version: 1.0 In-Reply-To: References: <1349305214-3241-1-git-send-email-yinghai@kernel.org> <20121004174746.GA24119@google.com> From: Bjorn Helgaas Date: Thu, 4 Oct 2012 14:47:56 -0600 Message-ID: Subject: Re: [PATCH 0/4] ACPI: kill acpi_pci_root_start To: Yinghai Lu Cc: Len Brown , Greg Kroah-Hartman , Andrew Morton , Linus Torvalds , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1784 Lines: 35 On Thu, Oct 4, 2012 at 2:14 PM, Yinghai Lu wrote: > On Thu, Oct 4, 2012 at 12:44 PM, Bjorn Helgaas wrote: >> >> To answer your specific question, yes, I do think drivers that are >> statically built in probably should be registered before devices are >> enumerated. That way, the boot-time case is more similar to the >> hot-add case. >> >> Obviously, for drivers that can be modules, the reverse must work as >> well (enumerate devices, then load and register the driver). And then >> the other order (register driver, then enumerate device) must also >> work so future hot-adds of the same device type work. > > so you will have to handle two paths instead one. I'm not proposing any additional requirements; I'm just describing the way Linux driver modules work. Any module *already* must support both orders (enumerate devices then register driver, as well as register driver then enumerate and bind to a hot-added device). And this should not be two paths, it should be one and the same path for both orders. > current booting path sequence are tested more than hot add path. True. You're proposing fiddling with driver binding order so we can use the current boot path ordering at hot-add time. I'm suggesting that the "register driver then enumerate device" order is something we have to support for hot-add anyway, and that we should use the same ordering at boot-time. That's more change for the boot-time path, but I think it's cleaner and more maintainable in the long term. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/