From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gra-lx1.iram.es (gra-lx1.iram.es [150.214.224.41]) by ozlabs.org (Postfix) with ESMTP id F1197DDE33 for ; Fri, 7 Sep 2007 18:21:52 +1000 (EST) From: Gabriel Paubert Date: Fri, 7 Sep 2007 10:21:43 +0200 To: Scott Wood Subject: Re: [RFC/PATCH 1/2] Basic generic time/clocksource code for PowerPC Message-ID: <20070907082143.GA27058@iram.es> References: <18144.4514.601900.881855@cargo.ozlabs.ibm.com> <20070906165535.GA11420@iram.es> <20070906170123.GA17990@ld0162-tx32.am.freescale.net> <20070906170547.GA12432@iram.es> <20070906172415.GA18226@ld0162-tx32.am.freescale.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20070906172415.GA18226@ld0162-tx32.am.freescale.net> Cc: linuxppc-dev@ozlabs.org, Paul Mackerras List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, Sep 06, 2007 at 12:24:15PM -0500, Scott Wood wrote: > On Thu, Sep 06, 2007 at 07:05:47PM +0200, Gabriel Paubert wrote: > > On Thu, Sep 06, 2007 at 12:01:23PM -0500, Scott Wood wrote: > > > On Thu, Sep 06, 2007 at 06:55:35PM +0200, Gabriel Paubert wrote: > > > > So who will be in charge of updating the RTC now? The update > > > > every 11 min is there to stay on x86(-64) it seems. > > > > > > Put something in crontab to run hwclock periodically. > > > > I have many machines on which cron is not even installed. > > OK, so use something else that waits in a loop and periodically updates > the clock. It shouldn't be the kernel's responsibility. It ha been the kernel's reposnibility ever since the NTP code was included with the kernel. The only way to move it out is to agree to something with NTP folks. It is going to break working setups who rely on this feature, which is a big no-no. The solution now used by i386/x86-64/sparc64 is CONFIG_GENERIC_CMOS_UPDATE. Maybe powerpc should be switched to use something similar, but the generic code has some problems (it assumes that you have to set the clock on a half-second, which is not the case of the RTC on my boards to start with). Now I'm aware that some PowerPC RTC are messy to handle in a timer/interrupt/whatever because some hardware designers thought it was wise to put the RTC on a dog-slow bus like I2C. You have however a variable to disable this update if you want (no_sync_cmos_clock), set it to 1 by default but please let people that use (and need) the functionality enable it (even do it by default when the RTC access is fast). Gabriel