Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266684AbUJWFPQ (ORCPT ); Sat, 23 Oct 2004 01:15:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267303AbUJWFN1 (ORCPT ); Sat, 23 Oct 2004 01:13:27 -0400 Received: from viper.oldcity.dca.net ([216.158.38.4]:62694 "HELO viper.oldcity.dca.net") by vger.kernel.org with SMTP id S266538AbUJWFLr (ORCPT ); Sat, 23 Oct 2004 01:11:47 -0400 Subject: Re: How is user space notified of CPU speed changes? From: Lee Revell To: Alan Cox Cc: Linux Kernel Mailing List , Robert Love In-Reply-To: <1098444170.19459.7.camel@localhost.localdomain> References: <1098399709.4131.23.camel@krustophenia.net> <1098444170.19459.7.camel@localhost.localdomain> Content-Type: text/plain Date: Sat, 23 Oct 2004 01:10:37 -0400 Message-Id: <1098508238.13176.17.camel@krustophenia.net> Mime-Version: 1.0 X-Mailer: Evolution 2.0.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 890 Lines: 23 On Fri, 2004-10-22 at 12:23 +0100, Alan Cox wrote: > On Gwe, 2004-10-22 at 00:01, Lee Revell wrote: > > JACK needs to know the CPU speed, in order to calculate the DSP load > > among other things. It used to be a valid assumption that you could > > calculate it on startup and it would not change. > > No it did not. It has never been a safe assumption. OK, thanks. Still no answer to my original question though. JACK makes extensive use of microsecond-level timers. These must be calibrated at startup, and recalibrated when the CPU speed changes. How does JACK register with the kernel to be notified when the CPU speed changes? Lee - 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/