# acpi_task_0 takes 100% CPU



## LypsylateX (May 10, 2010)

Hi,

about one time out of five boots a task called acpi_task_0 constantly used 100% cpu. The system is an Atom 330. Dual core with multithreading, so this ends up as 25% CPU usage.

The only way I've been able to resolv this is by rebooting the machine.

Searching the net gives nothing, only one guy who had the same problem on another hardware. I've done some testing with a 8.0 system aswell, and if my memory serves me correct I had the same problem there on similar hardware, althou I'm not sure.

Anyone who can point me in any direction? 


```
host# uname -a
FreeBSD <snip>.net 7.2-RELEASE-p3 FreeBSD 7.2-RELEASE-p3 #1: Tue Aug 11 19:19:21 CEST 2009     <snip>@<snip>.net:/usr/obj/usr/src/sys
/<snip>  i386
```


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## handersen (Jul 1, 2010)

Did you get anywhere with this?
I read around a bit and came to the conclusion that it might be a BIOS version thing, but I have only seen this behaviour once and it did not start right away at boot so it will take some time until I can say for sure that it really helped..

My board in question is an Intel D945GCLF2 with the Atom 330.


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## LypsylateX (Jul 2, 2010)

handersen said:
			
		

> Did you get anywhere with this?
> I read around a bit and came to the conclusion that it might be a BIOS version thing, but I have only seen this behaviour once and it did not start right away at boot so it will take some time until I can say for sure that it really helped..
> 
> My board in question is an Intel D945GCLF2 with the Atom 330.



Nope. The problem still persists. 

And, yes, I have the problem on a D945GCL2 just like you.


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## handersen (Jul 2, 2010)

LypsylateX said:
			
		

> Nope. The problem still persists.
> 
> And, yes, I have the problem on a D945GCL2 just like you.



What bios revision are you running?
I went from version 0171 from 04/03/2009 to the latest, 0278 from 04/14/2010 and at least since reboot things have seemed normal.
Then again, the only time I ran into it was once after about 20 days of uptime, so I guess time will tell..

This is the post that led me to check the BIOS before further digging:
http://www.mavetju.org/mail/view_message.php?list=freebsd-acpi&id=3006497


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## LypsylateX (Mar 21, 2012)

handersen said:
			
		

> What bios revision are you running?



My motherboard went down in a cloud of smoke (!) a couple of months later. Since then I'm running an Atom-board with another chipset.

I haven't had this problem with the new board.


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## handersen (Mar 31, 2012)

Hehe, well that*'*s one kind of self-solving problem! 

On a more serious note, did it get overheated in relation to the 100% CPU issues? I have had my system run into this maybe two more times since the firmware upgrade, but it has always been off site so I have never had a chance to check for any physical trouble. 

Glad the other chipset works out for you, this is the only one I have had any problem with so far.


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## LypsylateX (Apr 1, 2012)

handersen said:
			
		

> On a more serious note, did it get overheated in relation to the 100% CPU issues? I have had my system run into this maybe two more times since the firmware upgrade, but it has always been off site so I have never had a chance to check for any physical trouble.



Nah, it was a short circuit in the PSU that took more or less everything else with it into death. The memory stick survived, somehow.


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