Re: built for Geode: Clock drift

From: Jordan Crouse
Date: Fri Dec 05 2008 - 12:17:00 EST

Harald Dunkel wrote:
Hi folks,

If I build a kernel for AMD Geode, then I see a clock drift of appr.
30 min. to 1 hour per day. If I build the same kernel for i486, then
the clock drift is gone. Running ntp makes no difference.

Hardware is a Linutop PC. /proc/cpuinfo says

processor : 0
vendor_id : AuthenticAMD
cpu family : 5
model : 10
model name : Geode(TM) Integrated Processor by AMD PCS
stepping : 2
cpu MHz : 0.000
cache size : 128 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 1
wp : yes
flags : fpu de pse tsc msr cx8 sep pge cmov clflush mmx mmxext 3dnowext 3dnow
bogomips : 429.05
clflush size : 32
power management:

BTW, the CPU is running with 500 MHz (AFAIK). 0.000 MHz is surely not
correct. /proc/cpuinfo reports the same for both kernels.

Hmm - we've heard reports of this before, but nothing came of it. I would be interested in a chance to debug it this time.

Please try turning off CONFIG_GEODE_MFGPT_TIMER=y and try again. Also, try something in the 2.6.28 family to rule out fixes in the timer subsystem.

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