From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 11 Oct 2003 00:45:41 -0400 From: Bill Fink To: LinuxPPC Developers Cc: Bill Fink Subject: Re: Time precision, adjtime(x) vs. gettimeofday Message-Id: <20031011004541.5eda8953.billfink@mindspring.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: On Thu, 9 Oct 2003, Ethan Benson wrote: > On Fri, Oct 10, 2003 at 01:12:54AM -0400, Bill Fink wrote: > > > > This discussion prompted me to finally ask about another clock related > > problem I see on the 867 MHz G4 systems at work. The clocks on > > these systems continuously run 0.2% slow (about 3 minutes per day). > > Apparently this is more than ntp can adjust for (using scaling), as I > > get many of these error messages in the log: > > is it a quicksilver G4? i maintain one of those and its time goes off > much faster then that (3 minutes within a couple hours). Yes I believe it's a quicksilver G4. clifford% cat /proc/cpuinfo cpu : 7450, altivec supported clock : 866MHz revision : 2.1 (pvr 8000 0201) bogomips : 865.07 machine : PowerMac3,5 motherboard : PowerMac3,5 MacRISC2 MacRISC Power Macintosh detected as : 69 (PowerMac G4 Silver) pmac flags : 00000000 L2 cache : 256K unified memory : 640MB pmac-generation : NewWorld > the fix is rather simple: > > --- linux.old/arch/ppc/platforms/pmac_time.c.orig Sat Nov 30 02:33:49 2002 > +++ linux/arch/ppc/platforms/pmac_time.c Sat Nov 30 02:33:22 2002 > @@ -262,7 +262,9 @@ > * calibration. That's better since the VIA itself seems > * to be slightly off. --BenH > */ > +#if 0 > if (!machine_is_compatible("MacRISC2")) > +#endif > if (via_calibrate_decr()) > return; Thanks for the suggested fix. I'll give it a try when I get a chance. > in the case of the quicksilver VIA is FAR better then whatever it uses > instead. Assuming the fix works, is there a simple way to test for the quickserver G4 model rather than doing the "#if 0", since I like to run a common kernel across a variety of different processor models. -Bill ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/