From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755614Ab2AQUI2 (ORCPT ); Tue, 17 Jan 2012 15:08:28 -0500 Received: from lxorguk.ukuu.org.uk ([81.2.110.251]:50844 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751959Ab2AQUIZ (ORCPT ); Tue, 17 Jan 2012 15:08:25 -0500 Date: Tue, 17 Jan 2012 20:09:42 +0000 From: Alan Cox To: Simon Glass Cc: LKML , Greg Kroah-Hartman , linux-serial@vger.kernel.org Subject: Re: [PATCH 2/3] serial: Make wakeup_capable a flag to reduce boot time Message-ID: <20120117200942.7e7adf09@pyramind.ukuu.org.uk> In-Reply-To: <1326826563-32215-2-git-send-email-sjg@chromium.org> References: <1326826563-32215-1-git-send-email-sjg@chromium.org> <1326826563-32215-2-git-send-email-sjg@chromium.org> X-Mailer: Claws Mail 3.7.10 (GTK+ 2.24.8; x86_64-redhat-linux-gnu) Face: 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 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 17 Jan 2012 10:56:02 -0800 Simon Glass wrote: > The synchronize_rcu() call resulting from making every serial driver > wake-up capable (commit b3b708fa) slows boot down by 600ms on my Tegra2x > system (with CONFIG_PREEMPT disabled). > > Waking up the machine from a serial port seems to be an unlikely > requirement, so make serial_core default to not using the behaviour. Its quite normal on x86, and very very common on embedded. Sorry someone needs to fix the root cause not hack the driver. The other question would be whether in PC space you can deduce the wake up situation from ACPI data ? One for Len ? Alan