From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from zipcode.az.mvista.com (unknown [65.200.49.156]) by ozlabs.org (Postfix) with ESMTP id 2AB6ADDDFB for ; Sat, 13 Oct 2007 07:30:37 +1000 (EST) Date: Fri, 12 Oct 2007 14:30:41 -0700 From: "Mark A. Greer" To: Rune Torgersen Subject: Re: Override timer interrupt Message-ID: <20071012213041.GB22894@mag.az.mvista.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Cc: linuxppc-embedded@ozlabs.org List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, Oct 12, 2007 at 03:43:39PM -0500, Rune Torgersen wrote: > Is there an easy way to use something other than the decrementer for the > timer interrupt? > > Reason i'm asking is tha t on our board, the decrementer cannot be > divided to 1khz evenly, so we have rounding errors for time, but we do > have a 1KHz timer interrupt from an FPGA that is source of a T1 clock. > > Right now I let the decrementer interrupt do nothing, and made my own > timer interrupt handler that calls the stuff the timer_interrupt usually > does. > > This works, but there are some instability (ie unexplained hangs) that > showed up when I did this. Check out the clocksource stuff. It let's you set up numerous clock sources and set the rating of each one. You can start looking in arch/powerpc/kernel/time.c for example code. Mark