Why is my ThinkPad T60 trackpoint not recognized as a device?

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On my ThinkPad T60, the touchpad works fine but the trackpoint does not work at all. Why that?

Details and Diagnostics:

  • The trackpoint is enabled in BIOS.
  • The UltraNav tab of the Windows 7 mouse settings dialog shows the trackpoint as disabled (not possible to enable it) and the touchpad as enabled (not possible to disable it). This is exactly the same as how it looks when disabling the trackpoint in BIOS, but keeping the touchpad enabled there.
  • The problem is the same in all OS I tried (Windows 7, Ubuntu Linux 14.04).
  • A BIOS update from 2.23 to 2.27 did not help.
  • It's not a trackpoint hardware defect: exchanging the keyboard with the trackpoint for a working one did not help.
  • The trackpoint device does not appear under either Windows 7 or Linux. In Linux, xinput list only shows the touchpad (Synaptics Touchpad id=10), but should also show something like TPPS/2 IBM TrackPoint id=11.

tanius

Posted 2014-12-19T19:05:13.270

Reputation: 515

Answers

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This can happen through a hardware defect of the touchpad. It did, in my case.

That's right: a defective touchpad, even though working flawlessly as a pointing device, can prohibit the proper recognition of the trackpoint. This seems to be possible because both are supposed to act as PS/2 active multiplexing devices – needed, because "normal" PS/2 only allows one keyboard and one mouse. And that's how they could interfere.

To see if this is the problem, either disable the touchpad device in BIOS, or physically disconnect it. (Be sure to switch off the computer and remove AC plug and battery before you disconnect it!) If the trackpoint starts working now, your touchpad seems flawed and should be replaced. The touchpads of ThinkPad T61 models are compatible. Independent of screen size, though that affects the touchpad cable length and is not an ideal fit (the cable can be exchanged individually, though).

Under Linux, the probing for PS/2 pointing devices happens in the i8042 PS/2 chip's driver. There are some options that might help you to fix the probing without replacing the touchpad, or at least to debug the problem. I did not have luck with that.

tanius

Posted 2014-12-19T19:05:13.270

Reputation: 515

Remove the keyboard (on that computer it's a single screw under the laptop in the center) and disconnect/reconnect the flexible ribbon cable that links the keyboard and the trackpoint to the system board. – None – 2014-12-19T21:37:36.780

Didn't help in my case, as even exchanging the keyboard did not help. But you're right, it can help. Same for the touchpad ribbon connector (4 marked screws to loosen under the notebook), since a touchpad issue can be the cause as shown above. Also, I've heard a report of one case where a pinched ribbon cable was the culprit. – tanius – 2014-12-19T23:53:16.377

Asked: 2014-12-19T19:05:13.270

Viewed: 851 times

Active: 2014-12-19T23:56:38.980