Re: 2.6.27: 0 MHz CPU and wrong system time on AMD Geode system

From: Alok Kataria
Date: Fri Oct 17 2008 - 18:17:50 EST

On Thu, Oct 16, 2008 at 9:48 PM, Antipov Dmitry <dmantipov@xxxxxxxxx> wrote:
> Jordan Crouse wrote:
>> Could you try a 2.6.26 kernel? That will confirm that this is a new
>> addition to 2.6.27.
> Both 2.6.26 and looks good (with CONFIG_GEODE_MFGPT_TIMER=y).

Can you try the attached debug patch, it puts a printk message and
will let us know what exaclty is failing during the calibration
There were some major changes in the 2.6.27 cycle related to tsc calibration.
Apart from the unification for 32 and 64bit, some checks were added in
the code to make the calibration process more robust, maybe this
specific machine is more prone to SMI's than other, as a result the
checks are a little to harsh for this one.

Along with the dmesg with this patch, could you also let us know how
much is the frequency that the (2.6.26) kernel calibrates and what the
actual freuqency is on that box ?

> Dmitry
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Index: linux-2.6/arch/x86/kernel/tsc.c
--- linux-2.6.orig/arch/x86/kernel/tsc.c 2008-10-17 14:56:23.000000000 -0700
+++ linux-2.6/arch/x86/kernel/tsc.c 2008-10-17 15:01:38.000000000 -0700
@@ -163,6 +163,8 @@

+ printk("DEBUG: pitcnt %d, tscmin %lu, tscmax %lu\n",
+ pitcnt, tscmin, tscmax);
* Sanity checks: