From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267382AbUHJBI5 (ORCPT ); Mon, 9 Aug 2004 21:08:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267385AbUHJBI5 (ORCPT ); Mon, 9 Aug 2004 21:08:57 -0400 Received: from viper.oldcity.dca.net ([216.158.38.4]:4047 "HELO viper.oldcity.dca.net") by vger.kernel.org with SMTP id S267382AbUHJBI4 (ORCPT ); Mon, 9 Aug 2004 21:08:56 -0400 Subject: Re: 2.4.x vs 2.6.x: denormal handling and audio performance From: Lee Revell To: Fernando Pablo Lopez-Lezcano Cc: linux-kernel , jackit-devel In-Reply-To: <1092099606.22613.12.camel@mindpipe> References: <1092079195.16794.257.camel@cmn37.stanford.edu> <1092099606.22613.12.camel@mindpipe> Content-Type: text/plain Message-Id: <1092100150.22613.16.camel@mindpipe> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Mon, 09 Aug 2004 21:09:10 -0400 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2004-08-09 at 21:00, Lee Revell wrote: > On Mon, 2004-08-09 at 15:19, Fernando Pablo Lopez-Lezcano wrote: > > Hi all, I've been trying to track weird behavior I'm experiencing when > > trying to use 2.6.x for "pro audio" applications > > In case anyone thinks this is an application bug, here are some links > pertaining to the P4 denormals-are-zero issue If the denormals-are-zero bit is the issue then I believe this patch should fix the problem. Lee --- arch/i386/kernel/i387_orig.c 2004-08-09 21:06:00.000000000 -0400 +++ arch/i386/kernel/i387.c 2004-08-09 21:06:05.000000000 -0400 @@ -34,7 +34,7 @@ memset(¤t->thread.i387.fxsave, 0, sizeof(struct i387_fxsave_struct)); asm volatile("fxsave %0" : : "m" (current->thread.i387.fxsave)); mask = current->thread.i387.fxsave.mxcsr_mask; - if (mask == 0) mask = 0x0000ffbf; + if (mask == 0) mask = 0x0000ffff; } mxcsr_feature_mask &= mask; stts();