XPS 8940, USB devices intermittently dropping out

Question

My XPS 8940 has three USB disk drives connected directly to the ports on the back of the machine and a Wacom tablet connected to the front of the machine. Intermittently, the disk drives become disconnected and then reconnect and also the Wacom tablet disconnects and reconnects. This causes applications to crash when this happens during a save activity. Has anyone experienced these problems? Thanks

DaveClem · Accepted Answer

First can I say a HUGE Thank You to you Ron for all your help.  At last I think the problem is solved. After implementing all the suggested changes, I was still experiencing problems. I looked in more detail at the actual disk drives themselves, Lacie PorscheDesign 4TB HDDs and I discovered that the firmware has a 'Energy Saving' switch that turns the drives off when 'not in use'.  Feeling confident that this would solve the problem, I set the switch to off and gave this a try.  Still not fixed !!!.  The last resort was to purchase two replacement dives; I choose Seagate Backup Plus 6TB HDDs.  For the past two days I have given the drives a thorough workout; No Problems.  So there must be some kind of a problem with compatibility, between Lacie drives and Dell.

CTG_8273 · Answer

What type of drives connected? Flash drives? External Hard Drives? If External drives are they self powered (Portable)? The portable drives are USB powered and are actually laptop drives in an enclosure.

If they are Flash drives what brand? All the same brand?

CTG_8273 · Answer

@DaveClem  For some reason @DELL-Cares sent me a PM about your system.  Moderator DELL-Cares to CTG_8273‎04-13-2021 06:32 PM Re: USB Intermittently Dropping Out   .Thank you for staying connected. I'm Karthik, and I will be assisting you.If I have understood correctly, you’re facing an issue with the USB disconnects. Unfortunately our support is limited as the system has Dixon's warranty. I would suggests you to contact Dixon's for further support on this   Now how did this PM get sent to me?

RoHe · Answer

@DaveClem Go into Device Manager and expand list under USB. Double-click every USB entry and if it has a Power Management tab (not all USB entries have it), uncheck the box "Allow PC to turn off...".

Then do the same thing for all entries under Human Interface Devices in Device Manager that have a Power Management tab.

Now reboot and see if that solves the problem.

DaveClem · Answer

Thanks Ron, I will try what you suggest this morning. Much appreciated

DaveClem · Answer

There are 2 x Lacie 4tb Design and 1 x Seagate 1TB drive. All have independant power supplies

RoHe · Answer

@DaveClem  - Let us know if the changes in Device Manager I suggested help, or not, because there are a couple of other settings that may still need adjusting...

DaveClem · Answer

Will do, I have made the changes you suggested and yesterday afternoon I didn't get any problems, will continue testing today and let you know

DaveClem · Answer

Hi Ron,  I have tested the changes for a few days now, and I still have the same problem. What is also happening is that when I try to btransfer a file from Adobe Lightroom to Adobe Photoshop, part way theough the file loading the disk would drop off-line and hang the machine. The two usb drives on my Dell have 'access lights' that flash when they are being accessed. However both lights come on permanently, even thoiugh I am not trying to access the second drive (It is just on-line) I have run the Dell Application that checks for driver updates and I am all up to date.  Just about reached the end of my teather. Spending more time booting and rebooting that using the machine. (I have completely uninstalled and reinstalled Lightroom and Photoshop)

RoHe · Answer

Sorry you're still having issues...

Did you unchecked all those boxes to "Allow PC to turn off..." on Power Management tabs for devices listed under USB and Human Interface Devices in Device Manager?

Try this:
Open the Windows Power & Sleep screen. Click Additional Power Settings. On next screen identify the active Power plan and click Change Plan Settings. On next screen, click Change Advanced Power Settings.

On that last screen, disable Hibernation, Hybrid Sleep, USB Selective Suspend, and PCI Express Link State Management. Save the changes to the Power plan and reboot. See if that helps...

BTW: How much RAM in this system?

DaveClem · Answer

Yes I did check all and have now unchecked them. I have 40gb of memory installed. Will try your suggestions tomorrow and let your know how it goes

RoHe · Answer

Did you mean 48 GB of RAM ? 40 GB is a very odd amount.

The specs indicate that Dell hasn't validated any amount of RAM in between between 32 and 64 GB in the XPS 8940. Doesn't mean it (eg, 48 GB) won't work, but when there are problems, that's something to think about..

Let us know if changing those Power plan settings helps.

DaveClem · Answer

Will let you know later how I get on. However, I am now starting to think it may be a memory issue. I do mean 40gb of memory. I was advised by a third party memory supplier's Techical Support department that I could add 32gb Upgrade to my existing 8gb. But given your last message, and my testing (formatted a 4tb disk and copied 3tb of data to it with no problems), I think it's highly probable that it is all tied up with memory.

RoHe · Answer

@DaveClem So you have 2x 16 GB + 1x 8 GB of RAM? In this case, RAM is only running in "single channel" mode rather than in the faster/more efficient "dual channel" mode. Dual channel requires a matched pair of modules in a bank (slots with matching color retention clips). And smack that 3rd party tech support person up side of his/her head!

I'd still change the Power plan settings first and test. If that doesn't help, I'd then pull out the 1x8 GB and just keep the 2x16.

NOTE: DIMM1 is likely the 2nd slot from the CPU, and the first module goes in DIMM1. The 2nd and matching module goes in DIMM2 which would be the 4th slot from CPU, with same color retention clips.

DaveClem · Answer

Sorry for any confusion, I have the original memory 2 x 4GB and 2 x 16GB third party memory

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XPS 8940, USB devices intermittently dropping out

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