Created attachment 133568 [details] left click and try and move trace With 4.12 based kernel it seems that the Thinkpad x250 under touchpad clicks are no longer reliably triggerable. When clicking in the bottom left corner and attempting to move a second finger to highlight some text the cursor is static. Right click is similarly affected. It is possible there is a reliable zone, though very very small or one is simply off the edge of the active area when it is reliable. I am attaching a evemu-record of an attempt to left click with my thumb and move within the click with a forefinger.
This seems to be a kernel bug. Once two fingers are down, the only updates we get from the device are ABS_MT_PRESSURE. See from 0.72011 onwards in the log. Can you figure out which kernel version this still worked with?
I can confirm I had similar issues on thinkpad x250. Switching the kernel to the LTS 4.9 series eliminated the problem. For reference, see https://bbs.archlinux.org/viewtopic.php?id=228673 Furthermore, this seems to be related to bug #101979. Seems like a kernel issue to me.
Ok this seems to work back in 4.11.9 and to have been broken in 4.12.8 and fixed again in 4.12.10 based kernels.
@Andy Thanks for the heads up. Unfortunately 4.12.10 hasn't hit my arch repo yet. When it does I will also confirm. I've also found a relevant touchpad two finger commit in linux 4.13. Care to try?
Closing for now, please re-open if it turns out to be something other than a kernel bug.
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