Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754085Ab1DGHaQ (ORCPT ); Thu, 7 Apr 2011 03:30:16 -0400 Received: from eu1sys200aog110.obsmtp.com ([207.126.144.129]:44347 "EHLO eu1sys200aog110.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751578Ab1DGHaO (ORCPT ); Thu, 7 Apr 2011 03:30:14 -0400 Message-ID: <4D9D67F5.8030703@stericsson.com> Date: Thu, 7 Apr 2011 09:29:57 +0200 From: Mattias Wallin User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.15) Gecko/20101027 Thunderbird/3.0.10 MIME-Version: 1.0 To: Stephen Boyd Cc: Russell King , "linux-kernel@vger.kernel.org" , "linux-arm-msm@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Saravana Kannan , Andrew Morton , Linus Walleij Subject: Re: [PATCHv5 1/3] ARM: Translate delay.S into (mostly) C References: <1302047800-26720-1-git-send-email-sboyd@codeaurora.org> <1302047800-26720-2-git-send-email-sboyd@codeaurora.org> In-Reply-To: <1302047800-26720-2-git-send-email-sboyd@codeaurora.org> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1304 Lines: 29 On 04/06/2011 01:56 AM, Stephen Boyd wrote: > We want to allow machines to override the __delay() implementation > at runtime so they can use a timer based __delay() routine. It's > easier to do this using C, so let's write udelay and friends in C. > > We lose the #if 0 code, which according to Russell is used "to > make the delay loop more stable and predictable on older CPUs" > (seehttp://article.gmane.org/gmane.linux.kernel/888867 for more > info). We shouldn't be too worried though, since we'll soon add > functionality allowing a machine to set the __delay() loop > themselves, thus allowing machines to resurrect the commented out > code should they need it. > > Nicolas expressed concern that fixed lpj cmdlines will break due to > compiler optimizations. That doesn't seem to be the case since > before and after this patch I get the same lpj value when running > my CPU at 19.2 MHz. That should be sufficiently slow enough to > cover any machine running Linux. Tested-by: Mattias Wallin Yours, Mattias Wallin -- 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/