After disabling TCO_EN SMI#, problem disappeared.
The only question now is: Are there any side effects?
When you disable all devices than can assert SMI# to CPU, is there any danger of overheating CPU or any other part on the motherboard?
Thanks,
Slavisa Zigic
Slavisa Zigic wrote: : I disabled Thermal Management (TM1 & TM2) by writing 0x81 to : IA32_MISC_ENABLE. Bit 3 is Thermal Monitor 1 (TM1) enable, bit 13 is Thermal : Monitor 2 (TM2) enable.
: Nothing changed regarding 250us CPU stall.
: Slavisa Zigic
: Slavisa Zigic wrote: : : Cyril Novikov wrote: : : : On 05.06.2006 14:39, Slavisa Zigic wrote: : : :> Hello, : : :> : : :> I am using AAEON motherboards, models MB-845GE and EMB-845GE. The system is : : :> hard real time where response is expected in few microseconds. I tried : : :> running different software, but no matter what I am running, there is : : :> "dead-time" of approximately 250 us. This means that every few minutes, CPU : : :> will stop executing program for 250 us and then continue. I tried two : : :> different CPUs, P4 at 2.8 and 1.7GHz and both are showing the same problems. : : :> I also tried the same CPUs in two motherboards from different manufacturers : : :> and there is no "dead-time" on CPU. The only common thing on two different : : :> motherboards is the same Intel 845GE chipset. I also found that PROCHOT# pin : : :> on CPU is always asserted (logic '0'). I am running all tests on DOS : : :> platform (no multitasking). : : :> It doesn't matter if you enable/disable interrupts or enable disable APIC. : : :> Any idea what is causing this?
: : : Most likely, SMI's. It's just been discussed:
: : :
formatting link
: : : -- : : : Cyril
: : Cyril,
: : I downloaded 845GE chipset datasheet and wrote a small program to read : : control/status registers. All registers in South Bridge have default : : settings, which means, SMI disabled.
: : Now, about MSR on Pentium... : : Do I have to write routine in assembly (inline, if I use gcc) or there : : is C library available for MSR access?
: : Thanks,
: : Slavisa Zigic