I found a way to disable SMI. Furthermore, I found that TCO_EN bit is
causing SMI#. I am using Intel 82801DB ICH4.
How safe it is to disable SMIs?
Is there any problem with overheating of CPU or any other side effect?
: I also have a real-time app that runs on P4. It is running on AAEON MB-845GE
: motherboard. CPU stalls for 250us for unknown reason. This event is not
: periodic, sometimes it is after less than a minute, sometimes you have to
: wait for few minutes. Motherboard is using Intel 845GE chipset. I downloaded
: datasheet for South Bridge and wrote small program to read SMI enable
: registers. All values are default (as specified in datasheet), that is, SMI
: After that, I disabled Thermal Monitor on CPU (TM1 & TM2) by writing to MSR
: IA32_MISC_ENABLE (bits 3 and 13). No change. Still have 250us stall.
: 'cli' did not help, disabling APIC didn't help, disabling ALL interrupts on
: PIC didn't help, writing to Intel Software Developers Forum didn't help...
: Slavisa Zigic
: :> > I have a real-time app that runs on a P4. The box we are running it on
: :> > has an Aopen i865PEa-7IF motherboard. We are using the On-Time RTOS.
: :> > We have found that every 37 seconds the app completely stops running
: :> > for 250 microseconds. Using a PCI bus analyzer we discovered that
: :> > between the last operation done by my app and when my app resumes
: :> > running shows 100's and 100's of I/O reads and writes to addresses B3,
: :> > EB, and 61. Googling on this has led me to believe that these accesses
: :> > are related to SMI's and SMM. I have disabled everything in the BIOS -
: :> > USB, LAN, power management, serial and parallel ports, modem, firewire,
: :> > MIDI and game ports - yet my app still stops and I still see these
: :> > accesses.
: :> >
: :> > Does anyone know how I can totally disable the SMI's?
: :> https://mail.rtai.org/pipermail/rtai/2005-July/012391.html
: :> http://www.yqcomputer.com/
: : The code at this link is for the AMD Geode GX-1. It is not applicable
: : to the P4.
: : -larry