Re: PROBLEM: system clock slow on Athlon AMD64 since 2.6.21

From: Disconnect
Date: Sat Jun 09 2007 - 12:49:37 EST

On 6/9/07, Mikael Pettersson <mikpe@xxxxxxxx> wrote:
According to your system description it seems that you have a
Targa Visionary laptop with a VIA chipset and a Mobile Athlon64.
If so, then you probably have the same problem I reported some time
ago: see <>
and the followup messages. The conclusion was that the chipset's
ACPI PM timer slows down when the CPU is in C2.

The workaround is to boot with processor.max_cstate=1.

I was seeing the same problem on a Ferrari 3200 (with ubuntu kernels)
but more recent kernels ( don't ever seem to
enter C2 at all - according to powertop (1.5) its always in C0. (And
yes, this solved the clock problem at the cost of power use.)

I can provide any additional details that might help, and I'm in a
decent position to test things right now.

processor : 0
vendor_id : AuthenticAMD
cpu family : 15
model : 12
model name : Mobile AMD Athlon 64 Processor 2800+
stepping : 0
cpu MHz : 800.000
cache size : 512 KB
fpu : yes
fpu_exception : yes
cpuid level : 1
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx mmxext lm
3dnowext 3dnow
bogomips : 1605.13
TLB size : 1024 4K pages
clflush size : 64
cache_alignment : 64
address sizes : 40 bits physical, 48 bits virtual
power management: ts fid vid ttp
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