Dell Studio 15/17/XPS & Other DPC spike issues - Workaround

Hey,

If you're having problems with DPC spikes on your Dell studio series (1535/1737 or 1735/1737) laptop....

Please place a support call with Dell and place your reference number in here.

I want to collect all the data and make sure the issue is resolved without charge to users.

This is an awesome laptop and it will just take a little genius and footwork to cure the issues.

Google search link, http://www.google.ca/search?hl=en&q=dell+dpc+latency&btnG=Search&meta=

Currently I'm experiencing 2000-2100us spikes every 4secs regardless of what I disable.

Another problem is ejecting the blu-ray drive via touch button or Fn + F10.

It causes a +16000us spike all the time, however if you use the soft eject via My Computer it doesn't cause this behaviour.

I placed a call today and fully explained the issue, my reference number is 636632010.

I explained both issues to Dell support and they are investigating.

The more reports we have in, the more serious they will take the situation.

 

Breakthrough!

Found this posting on the net, http://forum.sysinternals.com/forum_posts.asp?TID=837&PID=23533

I downloaded and ran Process Explorer. I suspended the acpi.sys thread under system and the spikes IMMEDIATELY disappeared in the DPC latency checker.

So I will have to speak with Dell again today and track down where the problem is.

One thing I noticed is when I suspended the acpi.sys thread, I can no longer eject my dvd drive via the touch control or Fn + F10. I have to soft eject from my computer.

Also the Wi-Fi/Bluetooth switch does not work when the acpi.sys thread is suspended as well.

Here is the post on notebook forums showing other users having problems with TS on the Studio series 15 & 17, http://forum.notebookreview.com/showthread.php?p=4634132#post4634132

This also could probably be easily fixed by removing the acpi support in Windows since we cannot disable it in the bios currently.

Update: I contacted Dell and reported what was re-iterated here and suggest they add an acpi option to the bios so it can be disabled and explained the problem and workaround again fully on my ticket so they don't mess it up.

Does anyone know if there is acpi patch for WinXP or updated acpi.sys file?

 

Make sure to leave your on wireless, etc before you suspend the acpi.sys thread or you won't be able to turn it back on until you resume it.

 

Audio is nice and cleaaaannnn now.

YAAAAY!

Software, firmware and bios updates are in order!

 

Mate I hate to say I told you so, but.... This problem in most cases in acpi.sys caused by a slow polling routine for power state. Having talked to a few hardware guys in the years this has been going on, the chances of getting this fixed with a BIOS upgrade are extremely slim to none.
1/ The chances that it is fixable in the system BIOS firmware is extremely low, if your system had EFI instead of a BIOS then your chances are better, but then those slow polling routines would not be needed.

2/ An extremely small portion of the user base will actually be affected directly by the issue, meaning there is a very low priority going to be placed on getting the issue fixed for that sub 1% critical issues base. It does not mean you should not try, don't be too expectant that just because you reported the issue that Dell will care or better still, fix it.

Disabling ACPI may be your savior here. The problem has existed for a long time and affects many different brands and systems. Its existed since windows 95, 98, 2000 days; Hobbes was one of the first people I knew that experienced it on FS1[Sony], N.G. I think had it on her Acer, Toshiba, last year many models, HP, off an on, Dell on several laptops. It has never been fixed either in the O/S or in the BIOS. Your chances of it being fixed now are sadly, low especially on an O/S that goes two major revs back.

BTW there is normally a BIOS option to set ACPI state and you could also turn off pluf and pray in the BIOS or set the BIOS type at install time to standard PC. For Vista and Win 7 users you have to do custom installes to get there. Not sure if Win7 even supports non-ACPI systems. Hardware profiles my be your only path here.

Dropping ACPI support may/will loose you quite a bit. On some systems the CPU is then throttled to 75%. Worse still on a couple of Toshiba models you could not get it to go more than 75% because the CPU fan speed was locked on slow.
If you do disable ACPI, then make sure you install one of the speedstep control utils to adjust it (if you can). Run your fans on fast if you can adjust them.
Use CPUz to check out your system and register states too.
Phil

 

If they the intel chipset they used on the motherboard will allow ACPI to be disabled from the bios we should be ok.

I'm not the only one to report that's why I suggested who ever is having the problem to report it to Dell which users have already done so.

My HP laptop had the same problem but it had the option to disable ACPI in the Phoenix bios.

THe Dell is using the Phonenix bios as well so if they can enable the option to control acpi in an software update we would have a better chance of fixing the problem easily.

I used a Shuttle xpc for years before switching to a laptop so the first time I encountered dpc issues was with my HP.

However it was easily fixed by disabling the wireless when using TS.

I'm going to create a script that I can run to toggle the acpi service before running Pro for now.

 

There is an acpi reg fix in the ms kbase but it didn't work.

I'm just happy there is an easy workaround. Suspend the thread before using TS Pro and then resume when I'm done.

Some users already returned their laptops and if they had this info it could have saved them some trouble.

Check how nice the system latency is with acpi.sys suspended (right) vs. when it's running. (left)

 

Is it easy to suspend ACPI.SYS?

Is spiking during DCP latency checker on a new lap top a system fault?

 

It's quite simple.

You will need to download and install the Microsoft debugging suite. However, it will directly lead you there so you can download and install it.

In process explorer you would double click system and then locate acpi.sys, select it and click suspend.

I had the dpc latency tool open to see the direct results when I did this.

Refer to the article link I provided above for more information.

You will need to resume the acpi.sys thread after you're done using TS Pro, etc because your wifi/bluetooth switch and dvd eject buttons won't work.

Are you seeing spikes in the dpc latency tool?

 

The spikes are of the charts! I returned Dell from Hell and Im considering a Mac. What do you think? Is this good enough to run TSP?:

Macbook
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Im also helping a friend of mine that has spiking issues. He has downloaded Debugging Suite, but I cant find the Process Explorer you are talking about. Where can I find this?
Can you give me a step by step explaination on have to suspend ACPI.SYS?

 

Here is where you can get process explorer, http://technet.microsoft.com/en-us/sysinternals/bb896653.aspx

Here is where you get the debugging suite, http://www.microsoft.com/whdc/devtools/debugging/installx86.mspx#a

1. Install the debugging suite and reboot.
2. Extract the process explorer application.
3. Launch the DPC checker tool
4. Launch Process Explorer
5. Double Click on the System Node in the Process Explorer
6. Locate the acpi.sys thread (It was #152 on my system, it could be different for you)
7. Click on it so it's highlighted
8. Click suspend
9. Check DPC latency tool graph to see if the spikes have stopped.

If the spikes have stopped and you're in the 'green' in the DPC latency checker, you should be able to run TS Pro flawlessly at this point.

After you're doine using TS/TS Pro, go back into the Process Explorer, locate the acpi.sys thread, select it and click resume. Check the DPC latency checker and the spikes should return indicating acpi.sys is running again.

 

Thanx a million djQuartz I`ll check it out!

 

No problem, the Dell's are sick laptops. Just this issue exists currently and I did forward this thread to one of the support agents I spoke with over the weekend.

He escalated it to his manager and he emailed me back to let me know they are investigating.

Also, I have a feeling this could possibly fix DPC spikes on any system because the original article I posted was from a user with a custom built system who had these issues.

So the solution is for desktop and laptop problems with DPC interruptions on Windows.

 

Aight. I`ll take the Dell back if this fixes it
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Could you please keep me posted on the replies you get from Dell? If they adress this issue, Dell is a nice choice for Scandinavians (seriously reduced price in respect to what you get for the bucks.)

 

No problem, I will update this thread when I have some new information.

 

OK tried it out. Only found 2 threads: acpi.sys+0xf9fc and acpi.sys!DeregisterOpregionhandler+ox364e

Was unable to suspend either of these. Got the following error message: Unable to access thread, system can not find specified file.

Any ideas?

 

The first thread mound be the one to suspend.

However did you install the debugging stuff first and reboot?

 

Sure did!

 

Remember too you need to be an admin on the box to kill or suspend a process or thread.

 

Admin on the box?
What the what?