05-14-2019 09:38 AM - edited 05-14-2019 09:40 AM
I've just got a new T480s (about a day old as of posting), and right out of the box when going through the Windows 10 configuration I noticed that there was something strange about the touchpad. It was sluggish in responding to my movements, adding just enough input lag to throw off my perception of where the cursor would end. After using the laptop for a day, I noticed that the problem is intermittent - at times the touchpad works wonderfully, feeling very snappy to my finger movement. However, it can easily and very suddenly turn into a sluggish experience. it eventually recovers, but also reverts back to sluggish not too long after. Using an external mouse through USB has no such issue.
I cannot tell what causes the input lag; it appears random. It looks like this (the lag occurs at the start of the video and around 2:30 it's perfect):
All Windows and Lenovo Vantage updates have been installed. Device Manager states "ELAN Input Device For WDF" to be at 18.104.22.168, which appears to be the latest available for the T480s.
It doesn't look like I'm the only one experiencing this issue:
There's also a promising thread for the P52:
At page 11 someotherguy has released a beta ELAN driver which seems to resolve input lag. It would be great if something similar can be rolled out to the T480s! The lag mars the overall experience of the product which would otherwise have been excellent.
05-15-2019 08:22 AM - edited 05-15-2019 08:24 AM
Hi Quantom8! Welcome to our forums community. Could you try uninstalling and reinstalling the touchpad driver from the device manager? Try the steps here: https://support.lenovo.com/us/en/videos/vid500013. Hope that will work for you.
05-15-2019 12:25 PM
I'm checking with touchpad team whether T480s uses same touchpad as P52, and if so, whether it might be the same problem as discussed in P-series forum. Please wait a bit while I research this. Thanks for your patience and sorry for this trouble.
05-16-2019 01:46 AM
I have the same problem on my T480s too. The touchpad is lagging and sluggishness. It's just so annoying when even working daily tasks.
Please investigate and fix this issue asap!
05-16-2019 06:19 PM
05-16-2019 06:59 PM
ELAN is not sure whether this could be same problem that was reported on P52 or not. Could you please collect a log by following the instructions in the attached document? The idea is to reproduce the problem between step 4 and step 5. Appreicate your help with this.
05-16-2019 08:36 PM - edited 05-16-2019 08:38 PM
I apologise for the bad timing, but it seems that the issue has been fixed with a replacement of the trackpad. I had raised a support ticket several days back, and a Lenovo engineer came over some 1.5 hours ago to swap out the trackpad.
Interestingly, as he was testing the trackpad (before making the swap), we started seeing stronger artifacts not previously seen - the cursor refused to follow finger movement and started "hugging" or "rubber-banding" towards the left of the screen. It was impossible to use the trackpad to control the cursor.
I've been giving the new trackpad some light use over the last 1.5 hours and I'm cautiously optimistic that the problem has been fixed. It's surprising that this turned out to be a hardware issue. Could it perhaps be a bad batch of trackpads that made it out of the factory?
In any case I'll give someotherguy's instructions a go and report back with a log so that we can start taking references.
05-17-2019 12:20 AM
It's been 5 hours and I've not seen any input lag so far. Amazing.
As promised I went ahead and made an ELAN log anyway. What I did roughly was:
1. Drew a square shape with the cursor repeatedly, moving my fingers quickly from one side of the square to another. In the past with the old trackpad the lagged movements was very obvious as the cursor played catch-up with my finger.
2. Scrolled through some web content using the double-finger scroll.
3. Used the three-finger swipe to switch between windows.
4. Tapped four fingers on the touchpad to bring up the side control bar thingy in Windows 10. Tapped once more to close the bar.
5. Drew some more squares.