Precision 7510 Intermittent Mouse Issues

Question

(TL;DR) If you are experiencing issues matching one of the descriptions below, please send me a Private Message! I bought a new Dell Precision 7510 in October 2016, and it didn't take long for me to notice that the TrackStick will occasionally stop responding. This is most noticeable when clicking-and-dragging, for example, when selecting text or moving a window. In general, the TrackStick is not completely unresponsive when this happens - sometimes it just stutters a bit, sometimes it freezes completely but letting go of the mouse for a second or pushing the TrackStick really hard will make it respond again. Regardless, the problem is incredibly annoying and disruptive to my work. There are also occasional problems with the TouchPad - sometimes clicking a TouchPad button while I have a finger on the TouchPad would cause the pointer to jump to the bottom right corner of the screen and become unresponsive for 1-2 seconds. I contacted Dell Support, and they sent me a new Palm Rest and Keyboard. The new Keyboard didn't seem to have any impact on the behavior, but the new Palm Rest did. With the new Palm Rest, the TrackStick freezes happen much less frequently (although they do still happen occasionally), but the TouchPad will freeze periodically (at about the same frequency as the TrackStick freezes on the original Palm Rest, but without the pointer jumping to the bottom right corner of the screen as with the TouchPad issue on the original Palm Rest), and occasionally the TrackStick will move the pointer (I used some very low-level debugging tools to determine that it was the TrackStick causing these movements) as if it were being touched when my hands are nowhere near the TrackStick (like when I am holding a phone with one hand and typing on the number pad with the other hand). As it turns out, I also had several other unrelated issues with the laptop, so Dell eventually just sent me a whole new laptop. The new laptop solved all of my other unrelated issues, but the new laptop still had the same TrackStick/TouchPad issues as the original laptop with the original Palm Rest, although on the new laptop the mouse issues happen even more frequently. However, swapping either of the two Palm Rests from the original laptop into the new laptop made the new laptop behave the same as the original laptop with the same Palm Rest. After months of troubleshooting, I’ve learned a number of things (that apply to both laptops and all three Palm Rests): * The mouse issues occur in both Windows and Linux, and the triggers and symptoms (for any given Palm Rest) are identical in each OS (although the triggers and symptoms vary slightly between different Palm Rests). Using debugging tools in Linux, I am able to confirm that the Alps device actually stops sending hardware interrupts when the pointer stops responding. External mice are unaffected – when the TrackStick or TouchPad is frozen, an external mouse continues to work fine. * The mouse issues occur much more frequently when there is high-frame-rate video activity on the Intel video card. For example, scrolling a web page with lots of animated advertisements on it will often cause the mouse to become briefly unresponsive. Opening a command prompt and running a command that prints lots of output, or running an OpenGL benchmark on the Intel video card will typically cause the mouse to become almost completely unresponsive as long as the command or benchmark is running. However, simply playing a video typically will not cause the mouse to become unresponsive (I presume because videos have a fixed frame rate that is not high enough to trigger the issue). * High-frame-rate video activity on the nVidia card does not trigger the issue. Disabling 'Switchable Graphics' in the BIOS (which disables the Intel video card and forces the nVidia card to be used instead) effectively fixes the problem. However, unfortunately, using the nVidia card also dramatically reduces the battery life and makes the laptop generate much more heat. * The mouse issues do not seem to be affected by CPU/Disk/Network/other activity. Only video activity seems to correlate with the problems. For example, opening a remote desktop to another machine and running a command in a command prompt on the remote desktop that prints lots of output is sometimes enough to trigger the mouse issue on the laptop. * The mouse issues occur much more frequently when the laptop is running on A/C power than when it is running on battery. The issues do still occur when running on battery, but much less frequently. Plugging in an A/C adapter with neutral and ground connected but with the hot wire disconnected behaves the same as running the laptop on battery. (Indicating that this is not simply a ground noise problem when using the A/C adapter.) Plugging the A/C adapter into a UPS or an isolation transformer or a stand-alone generator does not change the behavior relative to plugging the A/C adapter directly into commercial power. (Indicating that this is also not a problem with noise on the hot wire.) * Removing all Alps drivers and forcing the TrackStick/TouchPad to run in PS/2 compatibility mode seems to make the mouse issues occur much less frequently. However, this also disables all of the multi-touch and scrolling capabilities of the TouchPad/TrackStick. * I’ve tried many different versions of both firmware and drivers in both Windows and Linux, and the issue is the same with all of them (as long as the Alps device is not switched to PS/2 compatibility mode). Other than the 'Switchable Graphics' setting, no other BIOS settings seem to have any impact on the issue. In particular, the C-States and SpeedStep settings DO NOT change the behavior. A couple months ago, my Dell Support case was escalated to the Dell 'Resolution Expert Center' (or 'REC'), and they got some Dell engineers involved. However, since then, things have pretty much stalled. I sent the REC my original laptop with its original palm rest, and gave them several test cases to try to reproduce the issue. They were able to reproduce the issue by running 'for /l %a in (1,1,1000000) do echo %a' in a command prompt. However, their engineers responded to that with some nonsense about a 'for' loop being unsupported 'syntax that has been built for third party purposes' (what does that even mean?) that is 'possibly allocating the wrong amount of memory when running this command causing the system to become intermittently unresponsive.' (I can demonstrate that it is not allocating the wrong amount of memory, and I can also demonstrate that this command doesn’t cause issues on many other Dell laptops, but they refuse to discuss this particular command with me any further.) They also claim they were unable to reproduce the issue by running any of my other test cases. So, I recently had them send me back the original laptop (thinking maybe they found some magic firmware update, driver update, setting, or something else I’ve missed that makes the issue go away for everything but the 'for' loop), only to discover that they hadn’t even installed one of the OpenGL benchmarks I asked them to test on it. At this point, they are telling me there is nothing more they can do for me, in part because they have 'no other cases in the REC like this as we track potential systemic issues.' However, I have found a number of similar complaints about the TrackStick and/or TouchPad on Dell Precision 7510 laptops around the web, so I’m confident this issue isn’t isolated to my two laptops. I’m hoping to get the REC/engineers to take one more stab at reproducing the issue with one of my laptops. However, I think it would also help to gather reports from other users experiencing the same issue. If you happen to have a Dell laptop with symptoms matching my description above, please send me a Private Message (Go to http://en.community.dell.com/user/conversations , click 'New', and type 'TopQuark_net' in 'Recipients') so we can make sure your issue gets reported to the REC. If you have problems sending me a Private Message, please post a response to this thread. Keywords: TouchPad TrackPad TrackStick PointStick

TopQuark_net · Accepted Answer

I've recently discovered that the exact placement of the fingerprint reader ribbon cable relative to the Alps chip underneath the TouchPad influences this mouse behavior, and detaching/removing the fingerprint reader ribbon cable from the system fixes this issue entirely on both of my laptops!

The fingerprint reader ribbon cable has adhesive on one side, and it is adhered to the inside surface of the palm rest. It runs across the TouchPad circuit board right next to the Alps chip on that board. The exact placement of the ribbon cable relative to the Alps chip varies slightly between palm rests - one of my palm rests came from the factory with the ribbon cable touching the Alps chip, while another palm rest came from the factory with the ribbon cable about 1mm away from the Alps chip. The closer this ribbon cable is to the Alps chip, the worse the mouse issues seem to be. The mouse issue seems to occur whether or not the ribbon cable is actually connected on either end, so I don't believe the fingerprint reader itself is causing interference. It seems like the fingerprint reader ribbon cable is acting as an antenna and is picking up interference from the video card and reflecting it into the nearby Alps chip, perhaps via capacitive coupling between the ribbon cable and the long straight traces on the TouchPad circuit board that happen to be directly underneath the ribbon cable. I suspect that slight variances in the placement of this ribbon cable during assembly of the palm rest might explain why replacing the palm rest seems to fix the issue for some people but not others.

If you are experiencing these mouse issues and don't need the fingerprint reader, you can simply remove the fingerprint reader ribbon cable. Follow the detailed instructions in the Owner's Manual (topics-cdn.dell.com/.../precision-m7510-workstation_Owner's Manual_en-us.pdf) for removing the palm rest, unscrew the fingerprint reader from the palm rest to access the ribbon cable connector, then detach both ends of the ribbon cable, simply peel it off of the palm rest, and reassemble the system. The only tricky part is releasing the catches on the various ribbon cables. To release the ribbon cables for the keyboard, place your fingernail or a knife flat against the ribbon cable, slide it toward the connector, then pry the edge of the connector perpendicularly away from the ribbon cable - the catch will rotate outward and release the cable. To release the ribbon cables between the palm rest and the motherboard, hook a fingernail or a knife under the catch, and pull straight up (to slide the catch out parallel to the ribbon cable) - the catch will slide out slightly and allow the cable to be pulled out. The connectors on either end of the fingerprint reader ribbon cable are the same as the connectors for the keyboard ribbon cables and can be released in the same way.

Unfortunately, despite this new discovery, the Dell Resolution Expert Center and Dell Engineering still seem uninterested in correcting this issue. Hopefully this post will at least allow some other users to resolve this issue for themselves and avoid the nightmare that I have been through.

Kent F · Answer

Having similar problem with trackpad.  Will contact Tech support and point them to this link.  Thank you.

alaskanjackal · Answer

I had this issue as well, though only with the TouchPad, not the TrackStick.

Switching out the palmrest did not resolve the issue. Eventually, I sent the machine in to the Dell Advanced Resolution Center (shipping address in Houston) for that and several other issues (mainly, frequent BSODs) and they replaced most of the parts in my machine, including the motherboard. That appeared to resolve the issue.

However, the new motherboard had a video issue (the screen would only turn on after the computer was brought back from sleep about one in every three or four times), so they sent a remote tech out to replace the motherboard. Unfortunately, the new motherboard now has issues with the system audio, so I'm waiting to hear back from my contact when he is back in the office later this week.

Strangely, the TouchPad issue seems to have returned, though it is only about 10% as bad as it was before (instead of stopping for 10+ seconds every few minutes, now it stops for about 1-2 seconds every 10-20 seconds), and it only does it intermittently.

That all said, I don't have a fingerprint reader on this machine, so I'm unsure if your solution will work. Perhaps there still is a ribbon cable for one even though it isn't installed. If/when a tech comes out to replace yet another part later this week, I'll make sure to look at it and mention it to him.

For the amount of money spent on this machine, I'm getting a bit tired of this cat-and-mouse game!

Oh, seems like bull that they claimed they have "no other cases in the REC like this." I reported this issue to them almost immediately after my original machine arrived last June.

TopQuark_net · Answer

Interesting ... I have a video issue that sounds somewhat related. I typically work under Linux and I rarely sleep the machine, but I did use DPMS for a while to turn off the screen, and sometimes the machine would become completely unresponsive (even the network card would stop working) when re-enabling the screen. I was assuming this was a bug in Linux (and I simply turned off DPMS for now to avoid it), but maybe it is a hardware issue. I will do some testing in Windows to see if it happens there too.

Are you able to correlate the TouchPad issue with video activity at all? For example, does running “for /l %a in (1,1,1000000) do echo %a” in a command prompt make the problem worse? In my case, video activity seems to correlate with my mouse issues, so I wonder if we can determine whether your issue is really the same as my issue, or if it is something different with similar symptoms. If you don't have a fingerprint reader, then I doubt you have a ribbon cable for it ... but definitely worth checking if you happen to have the machine taken apart again.

As far as reliability goes, I totally agree. I spent a whole lot of money on this machine, in part because I am a power user and I needed a high-end machine, but mostly because I am heavily reliant on this machine for my work, I need a reliable system, and I assumed that the most expensive laptop Dell sells should be among the most stable and reliable. Luckily, with the exception of my mouse issues, Dell Support has been rather helpful and has been very willing to replace parts as I find issues. But the number of hardware issues I have encountered with this machine is rather ridiculous.

alaskanjackal · Answer

I haven't found any correlation between video activity and the TouchPad freezing. It seems pretty continuous and pretty random.

I just sent the machine to the ARC for a week of testing. It just came back with a fresh install of Win10 and a new palmrest/keyboard/TouchPad...and guess what, as soon as I started working on the machine, the TouchPad issue recurred.

Literally the ONLY thing I had done to it was open up the Windows Updates control panel, downloaded the recommended updates, and restarted.

Maybe I should take a different tactic and reinstall the OS virgin without any updates, play around with it for a few hours, and boot into Linux (will have to dig around for a spare USB drive to install a flavor of something on) and play around with that for a day and see if it occurs. If so, then I know it's hardware. If not, then I know it's software...but for it to happen on an almost-virgin Windows install leaves me skeptical and confused. Anyway, late now, so no sense beating my head up any more tonight. Will mess with it in the morning.

sergtech · Answer

Awesome Post, TopQuark.

I will see what happens when I disable the switchable graphics.

I also experience the issues in Windows and Linux, although not as seriously. They also seem to be related to running Chrome (on both OSes!).

marckusd · Answer

This seems to be the most relevant post i could find regarding the touchpad issues of the precision 7510. I also have an issue with the touchpad on my 7510 that is a bit different than the one described here. Only one part of my touchpad is non responsive. An area about one cm squared in the upper right center part of the touchpad ceases to function randomly and the rest functions properlly. The fix is to type something on the keyboard. i could not determine a constant time or some sort of trigger for the problem. If i type constantly on the keyboard or use the mouse buttons the issue does not happen. Also, the newest dell touchpad driver for the laptop causes it to hang after a few minutes of being turned on and it also makes the touchpad feel laggy and unresponsive.

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