MP BIOS bug: 8254

MyHeartPumpsFreon · 11-13-2007, 07:55 AM

Hey,

I just got an error that states "MP BIOS bug: 8254. Timer not connected to IO-APIC. I've researched this and it has to do with sending IRQ to multiple CPU's. Now I have an AMD 64 X2 4200, and Fedora 8 64-bit has been installed since Sunday. I only received this error when I installed a new PSU and video card last night at about 11:00EST. I've seen various fixes for this problem, but I have a question... will any of them make my processor lose functionality? I don't want to lose any performance if possible. Any help is appreciated.

Thanks,

Brandon

tredegar · 11-14-2007, 11:56 AM

Quote:

I've seen various fixes for this problem, but I have a question... will any of them make my processor lose functionality? I don't want to lose any performance if possible. Any help is appreciated.

Well, you have not told us what these "fixes" are, so we cannot comment on what they might or might not do.
However, it's unlikely you'll loose any performance.
I suggest you benchmark your PC, apply one of the fixes, and re-test it. All OK = Good. Something not right = Undo the "fix" you tried an try a different "fix".
Have fun

MyHeartPumpsFreon · 11-14-2007, 12:22 PM

Hey,

Sorry for being so vague. I posted this after I first woke up in the morning. NOt much of a morning person. The fixes I was referring to were posted in the Ubuntuforums.org: http://ubuntuforums.org/showthread.php?t=191355&page=1

The fixes consisted of passing 'noapic' to the kernel, or disabling it from the BIOS. I was thinking that if this was disabled, it would decrease performance. Can you suggest a decent benchmarking tool? I'm not familiar with any.

Thanks,

Brandon

tredegar · 11-14-2007, 12:53 PM

Quote:

Can you suggest a decent benchmarking tool? I'm not familiar with any.

Sorry, no. If my PC is working, I'm happy.
But passing noapic to the kernel is not going to affect your performance, only the way interrupts are allocated and handled by the kernel (which is concerned with performance, and will do things the very best way it can). So just try it

MyHeartPumpsFreon · 11-14-2007, 01:44 PM

Hey,

Thanks. T minus 3 hours and count before I go home and try it.

Regards,

Brandon

MyHeartPumpsFreon · 11-17-2007, 09:37 AM

Hey,

sorry it took me so long to get back. I've tried many switches from the grub menu and none of them work. The ones I've tried are: noapic--, nolapic, nolapic_timer. I've also tried looking in my BIOS to try and disable apic, but there is no such option. Anyone else have any ideas? It doesn't seem to be system critical, but it's kind of annoying seeing that pop up every time I boot.

Regards,

Brandon

MasterC · 11-17-2007, 10:44 AM

APIC is your Advanced Programmable Interrupt Controller. You may want to hunt around your BIOS for IRQ options. The one time I had similar messages from some hardware there was indeed an APIC option in the BIOS, you may just have to look for different names.

-Chad

tredegar · 11-17-2007, 11:39 AM

Kernel interrupt options I am aware of:

Code:

Interrupts are a complex aspect of kernel behavior. The boot time options deal
mostly with the interface between the kernel and the hardware that handles inter-
rupts, such as the Intel chip’s Advanced Programmable Interrupt Controller
(APIC).
apic              Change the verbosity of the APIC subsystem when booting.
                  apic=[quiet|verbose|debug]
                  Control how much information the APIC subsystem generates
                  when booting the kernel. The default is quiet.
noapic            Do not use any IOAPICs.
                  Prevent the kernel from using any of the IOAPICs that might be
                  present in the system.
lapic             Enable the local APIC.
                  Cause the kernel to enable the local APIC even if the BIOS had
                  disabled it.
nolapic           Do not use the local APIC.
                  Tell the kernel not to use the local APIC.
noirqbalance      Disable kernel IRQ balancing.
                  Disable all of the built-in kernel IRQ balancing logic.
irqfixup          Basic fix to interrupt problems.
                  When an interrupt is not handled, search all known interrupt
                  handlers for it. This is intended to get systems with badly broken
                  firmware running.
irqpoll           Extended fix to interrupt problems.
                  When an interrupt is not handled, search all known interrupt
                  handlers for it and also check all handlers on each
                  timer-interrupt.
                  This is intended to get systems with badly broken firmware
                  running.
noirqdebug        Disable unhandled interrupt detection.
                  By default, the kernel attempts to detect and disable unhandled
                  interrupt sources because they can cause problems with the respon-
                  siveness of the rest of the kernel if left unchecked. This option
                  disables this logic.

BIOS options differ, but if there is an option for "Enable PnP", disable it.

MyHeartPumpsFreon · 11-17-2007, 01:16 PM

Hey,

Thanks Tred. I'll try those when I get home. Chad... I looked everywhere in my BIOS. The only thing in there related to IRQ is for my parallel port and what IRQ number I'd like it to be or if I'd like to disable it. I've disabled it and it still comes up. there is NO other disable option for IRQ.

Regards,

Brandon