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#1 2010-04-25 12:30:10

sztomi
Member
Registered: 2009-01-25
Posts: 10

kacpi_notify going crazy

Hi,

I've got an issue with kacpi_notify. Very often, it goes crazy and eats 25% cpu constantly on a dual core machine. I couldn't find the exact reason causing it, but it happens a lot. After a day, 55 minutes of processor time was in kacpi_notify (according to top). The fans are spinning, and the machine temperature never seems to drop. Sometimes the mouse cursor is moving laggy.

I'm running kernel26-ck, but the exact same thing happened with the vanilla kernel.

I googled around a lot, and it turns out that it's a very common bug in the ubuntu world, with no apparent solution. The only advice I could find was to turn off ACPI in the kernel parameters, which I don't want to do, because it's a laptop, and having ACPI is quite essential for the battery state checking.

I tried changing the ACPI state by pulling the plug, but nothing happened.

Previously I ran debian, ubuntu, fedora, and a year ago arch, too. I never had this problem, and I didn't change my hardware. Does anyone have some good advice on where the start solving this problem? Thanks in advance.

Last edited by sztomi (2010-04-25 12:30:48)

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#2 2010-05-05 21:38:24

sztomi
Member
Registered: 2009-01-25
Posts: 10

Re: kacpi_notify going crazy

sad

It seems like nobody knows the answer. I tried multiple times on many IRC channels, and didn't get a single response. I'm thinking about firing up a debugger to see what's happening. Is it possible to debug a running kernel? It needs to be on the same hardware obviously.

Last edited by sztomi (2010-05-05 21:38:39)

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#3 2010-07-05 15:21:40

sztomi
Member
Registered: 2009-01-25
Posts: 10

Re: kacpi_notify going crazy

After some research I came to the conclusion that this might be a hardware issue. I can't prove it though, but the fact that there are some issues that are present on any OS I used, suggests that this is the case.

One might gather some info by compiling a kernel with ACPI debugging support.

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#4 2010-08-05 04:57:53

kcirick
Member
Registered: 2010-06-21
Posts: 364

Re: kacpi_notify going crazy

Has this been solved?

I've had the same problem with kernel > 2.6.34, and I've been trying some solutions, some of which are working.

The problem is posted here: http://goo.gl/H2iz
According to this, it's the patch to deal with negative temperature. The file that affects this is drivers/acpi/thermal.c, and you can see the diff here: http://goo.gl/infP

Basically, the patch removes the line "return -ENODEV;" and forces /proc/acpi/thermal_zone to be there, so kacpi_notify goes into infinite loop. The workaround is to revert this patch, or just insert "return -ENODEV;" back where it belongs.

Another solution, which I've been trying right now, is to edit the DSDT and recompile the kernel. As mentioned before, this whole thing is due to the faulty DSDT which results in negative temperature, so fixing the DSDT will fix this issue. Just follow the steps here: http://goo.gl/kKb6

I hope this helps.

BTW, my system is an old HP Pavilion 505n desktop from 2003.

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