# [SOLVED] Kernel panic on boot: IO-APIC error

## aryaniae

When I boot my Gentoo box, it says

 *Boot log wrote:*   

> .. MP-BIOS bug: 8254 timer not connected to IO-APIC
> 
> Kernel panic - not syncing: IO-APIC + timer doesn't work! Try using the 'noapic' kernel parameter.

 

If I boot with the 'noapic' parameter it works fine, but I assume that APIC is a good thing. (Besides, errors annoy me.  :Wink: ) 

I have and Asus M2N-SLI motherboard with an nForce-MCP55 chipset and an AMD Athlon64-X2 processor. I'm using gentoo kernel 2.6.18-hardened. 

I assume there's a kernel module I have to turn on, but I can't seem to find it.

Here's my lspci output relevant to the chipset, in case that helps (I left out the lines about IDE, SATA, ethernet, USB, IEEE 1394, and audio). 

 *lspci wrote:*   

> 00:00.0 RAM memory: nVidia Corporation MCP55 Memory Controller (rev a1)
> 
> 00:01.0 ISA bridge: nVidia Corporation MCP55 LPC Bridge (rev a2)
> 
> 00:01.1 SMBus: nVidia Corporation MCP55 SMBus (rev a2)
> ...

 Last edited by aryaniae on Fri Jan 26, 2007 7:46 am; edited 1 time in total

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## ikshaar

Please use search function before to post...

https://forums.gentoo.org/viewtopic-t-532789-highlight-m2nsli.html

Answer: upgrade your BIOS.

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## aryaniae

Thank you. Upgrading to 0807 fixed it.

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## rgviza

If your BIOS isn't patched, and none is available, the kernel now handles MCP-55 timer issues with acpi_use_timer_override. While not applicable to this motherboard in particular (since the mfgr patched the BIOS and  you don't need the switch) other NF3-5x/MCP-55 boards are EOL'd and no longer supported with bios updates so the issue persists.

noapic/irqpoll binds all interrupts to one cpu. While it stabilizes the kernel it's not the optimal solution. With the acpi_use_timer_override switch I'm  getting interrupts on both CPUs though CPU1 is favored (which is ok), and I'm stable.

here's the kernel.org bugzilla: http://bugzilla.kernel.org/show_bug.cgi?id=8368

Thought I'd throw this in since I'm in this boat (MCP-55, no bios update).

-Viz

Keywords: MCP-55, MCP55, UT590, UT-590, nForce 590, timer, kernel panic

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