Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755171AbZINM6X (ORCPT ); Mon, 14 Sep 2009 08:58:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751900AbZINM6W (ORCPT ); Mon, 14 Sep 2009 08:58:22 -0400 Received: from fg-out-1718.google.com ([72.14.220.154]:11601 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751547AbZINM6W convert rfc822-to-8bit (ORCPT ); Mon, 14 Sep 2009 08:58:22 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=v6DL66gIykTQZlhiBMzH7Nx3XcPkkeZd4jSFKp47TiWUjCGcvwMHGlH7rbksr1WG/E 8HrlCOYjmaCmovQqFKJm/ebPYhw9ZoKeK6qQhNcWTWpwhr/0RSOz8n8L26zqfkeAYITv oQMaOn0qb8EaIIMT1LmpbaWe+X/xZuwfQGB/w= MIME-Version: 1.0 In-Reply-To: <20090914081001.GB14519@n2100.arm.linux.org.uk> References: <1252875960-21512-1-git-send-email-felipe.contreras@gmail.com> <200909132328.47079.marek.vasut@gmail.com> <20090913230008.GC30169@n2100.arm.linux.org.uk> <20090914002100.GD30621@shareable.org> <20090914081001.GB14519@n2100.arm.linux.org.uk> Date: Mon, 14 Sep 2009 15:58:24 +0300 Message-ID: <94a0d4530909140558nd8d2c47lc9954563c80a574f@mail.gmail.com> Subject: Re: [PATCH] arm: remove unused code in delay.S From: Felipe Contreras To: Russell King - ARM Linux Cc: Jamie Lokier , Marek Vasut , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1192 Lines: 33 On Mon, Sep 14, 2009 at 11:10 AM, Russell King - ARM Linux wrote: > On Mon, Sep 14, 2009 at 01:21:00AM +0100, Jamie Lokier wrote: >> Russell King - ARM Linux wrote: >> > On Sun, Sep 13, 2009 at 11:28:47PM +0200, Marek Vasut wrote: >> > > >                 bhi     __delay >> > > >                 mov     pc, lr >> > > >  ENDPROC(__udelay) >> > > > >> > > Hi >> > > >> > > why was this code there in the first place ? >> > >> > To make the delay loop more stable and predictable on older CPUs. >> >> So why has it been commented out, if it's needed for that? > > We moved on and it penalises later CPUs, leading to udelay providing > shorter delays than requested. > > So the choice was either stable and predictable on older CPUs but > buggy on newer CPUs, or correct on all CPUs but gives unnecessarily > longer delays on older CPUs. Why not add an #ifdef CPU_V4 or whatever? -- Felipe Contreras -- 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/