Re: clock skew on B/W G3
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: 2005-10-04 22:17:10
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On Tue, 2005-10-04 at 08:14 +0200, Marc wrote:
Hi, given that this option causes problems on non i386 systems, may I propose to mark CONFIG_HZ as broken on these architectures and/or use a default value of 1000 ? I guess this issue can't be fixed in a sane way until 2.6.14 is out.
The problem is indeed in via_calibrate_decr(). This routine works on HZ/100 so it will not do any good with HZ not beeing a multiple of 100. Can you test this patch ? Index: linux-work/arch/ppc/platforms/pmac_time.c ===================================================================
--- linux-work.orig/arch/ppc/platforms/pmac_time.c 2005-09-22 14:06:18.000000000 +1000
+++ linux-work/arch/ppc/platforms/pmac_time.c 2005-10-05 08:14:17.000000000 +1000@@ -195,7 +195,7 @@ ; dend = get_dec(); - tb_ticks_per_jiffy = (dstart - dend) / (6 * (HZ/100)); + tb_ticks_per_jiffy = (dstart - dend) / ((6 * HZ)/100); tb_to_us = mulhwu_scale_factor(dstart - dend, 60000); printk(KERN_INFO "via_calibrate_decr: ticks per jiffy = %u (%u ticks)\n",