Rene Schrieken

A DPC debugger, just basically looks at your device list. ( Deffered, usually means that its a device driver interupt that is being deffered ).

The DPC is being used by the Battery monitor which *ABSOLUTLY* *MUST* check the freaking battery every second. ( On my Sony Laptop, the battery monitor is OFF unless I am using the battery, then I turn it ON by a mouse click on the desktop ).

A battery cannot generate intrupts, but a APCI moniter device can. Turn off you battery monitor, and if possible TURN OFF APCI ( Heh, your going to really like this acronym: Advanced Power Control Interface... Have Fun!

Yours,

ArthurT

I don't know about any DPC debugger, but thank you for putting this in your blog all the way back in 2004. I have had the same problem and you have given me the non-obvious solution. I was just about to give up and  buy a new laptop (a Mac this time though).

We have an Acer Aspire 1640 laptop (1642WLMi). The problem was that the keyboard and trackpad were not working properly. Key strokes would be missed and the trackpad worked intermittently. It had become unusable over the last week or so. Plugging in a USB keyboard / mouse did work just fine - but hardly a practical solution.

Task manager showed a process with the image name "system" using 20 to 50% of the CPU. After some Google searching I downloaded Process Explorer, which showed the CPU was spending its time doing DPCs. So I eventually found your post searching Google for dcps keyboard.

I took out the battery (while powered by the mains adapter) and DPCs activity disappears on Process Explorer and the keyboard and trackpad work perfectly!

After plugging the battery in again the keyboard still works - maybe it was a bad connection? maybe the battery has to be warm? Time will tell.

It turns out the battery life has been lousy over the last year so the laptop has been used plugged in most of the time.

The laptop has been shutting down intermittently too so we'll try with the battery out for a while. If it is OK then maybe the battery is somehow causing the shutdowns and I'll just buy a replacement battery.

Thanks again!

Ran into the very same problem on my MacBook (running windows xp at the time via bootcamp)  My CPU usage started capping out so I went crazy looking for malware/spyware/virus and such and couldn't find anything.  Eventually ended up using processexplorer and seeing the DPCs then googling again.  Dropped the battery out and bam everything is back to 0% usage.  My battery still had some use out of it and I don't have the money to replace it so I'm looking for a way to still use it.

Thanks guys, for me it was the battery as well.

I took the battery out ehile powered by mains power and the system process (DPC's) dropped to basically 0.

and as such the cpu fan etc dropped down in noise etc. and I can use the pc again.

-strangest problem ive seen in my computing / support career, of 5-7 years.

Exact same problem as Jim above but with an Acer TravelMate 4060. Process Explorer told me that DPCs were hogging about 80% of my CPU. Removing the battery solved it. Keyboard and trackpad work perfectly now.

My battery is very old and barely holds a charge (always plugged in), so perhaps that's the cause. I successfully reinserted the battery without the CPU hogging. But the battery monitor showed it had 0% power left.

I had the same issue today with an Acer Travelmate 2312LMi_L. I solved the problem by disabling one of the two items under device manager / batteries: Battery that complies to the Microsoft ACPI standard (or something like that, it is a localized version of XP).

Had same issue with Acer Aspire 5672 Wmi.

Keyboard and Touchpad were disabled before login screen appeared. Only external mouse worked (on screen keyboard can be very useful).

Was able to boot a live Fedora Linux CD and all hardware worked fine so knew there was nothing hardware wise wrong.

The machine in question has very little battery life as it has almost always been connected to the mains.

Using dpclat.exe saw over 1000micro second latency. This dropped to sub 100 when I removed the battery and I got a driver error message. There after replacing the battery left me with low DPC rate but it slowly rose.

Not sure if a new battery would fix the issue but disabling ACPI works.

Thank you for this solution.

I had the same problem with my MacBook Pro. Removing the battery solved the problem, but after a reboot the problem came back. After removing the battery AND power adapter the problem disappeared.