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During general use my laptop (Lenovo Thinkpad Edge 15 running Ubuntu 12.10) will suddenly mute its volume and stall for a few seconds, seemingly for no reason. At the same time if I'm in a terminal the previous command is selected.

I have observed that the problem seems to occur if my wrists are resting on the laptop below the keyboard, to either side of the touchpad, but not if they're held above it. It has also seemed linked to using the nub mouse or the nub mouse scroll button (located between the left and right clickers directly below the space bar). Disabling the track pad has not helped the issue, though I have not tested disabling the nub mouse or associated buttons.

I installed a keylogger to help monitor and then used the system for a while, sure enough it happened a few times and I isolated the following series of keypresses that occur of their own accord:

<Up><E-71><LAlt><#+1>j<#+61>

The <# items seem to be a count, which is strange as the Lalt key would not normally record a count and I've not been able to press any combination which causes this in normal use. The number after the j seems arbitrary, from 1 up to hundreds. The E-71 key is the laptop's volume mute, on the F1 key (the F keys have a separate Fn trigger button).

At times the volume has switched on and off, I suspect with this process happening multiple times. I recreated it a single time by pressing hard on the laptop case to the left of the trackpad, but have not been able to do this again. So there may be a hardware element, though the laptop is otherwise in good working order and physical condition - it has never been dropped or suffered an impact, and this problem has only been occurring for a few weeks, without anything that comes to mind as a trigger for when it started.

It may be just a hardware problem, but if there are ways of working round it (the small stall is likely due to the weird key combination confusing the OS) I'd be interested, and more so if anyone else has experienced similar.

2 Answers 2

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I have to say that this is almost surely a hardware issue. If you just search for the term Thinkpad Edge 15 keyboard problem you will be presented with a lot of hits with similar (though not exactly the same) problems.

You can read through this lenovo forum about the problem. It has an accepted solution which basically tells to contact service.

You can also look at this blog entry to get a clue about what is the problem with the hardware and see a possible solution on how to repair it yourself. (As askubuntu doesn't deal with hardware issues I shouldn't provide the repair method here, since it is off-topic.)

I think that this kind of hardware issue cannot be dealt in software. Even if you filter out somehow that specific key-combo-chain which you have logged, it is likely that as time goes you will experience other problems with the keyboard.

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  • Please, when answering with links, provide at least brief summary of the contents. Those links will be broken sooner or later, and then this post is more or less useless.
    – Olli
    Feb 6, 2014 at 9:36
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    @Olli I DO NOT answer with links. I provided some links which contain further information. And I provided the relevant information from those links which tells us that the only possible solution is to contact the service. Nothing else from those links should be provided here. Also this post is not useless, it answers the question that it is a hardware issue, which according to my sources cannot be solved by software. Askubuntu doesn't deal with hardware issues so I shouldn't post solutions on how to repair the keyboard (from the second link).
    – falconer
    Feb 6, 2014 at 12:45
  • That hardware change sounds decent. I'll give you the bounty for unearthing that blog post!
    – M1ke
    Feb 10, 2014 at 11:23
  • To feedback on this, a few weeks ago I followed the solution listed on that page with the tape over the wire. I went a bit further and taped over all bare metal below the touch pad. Since doing that I have not encountered this error again and have been able to remove key bindings affecting my alt key.
    – M1ke
    Mar 24, 2014 at 12:23
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I've found the best solution so far. We can assume it's likely a hardware problem, as the key combination should not be possible (multiple Alt presses are not recognised normally, and disabling repeat key presses does not work).

However in my case the laptop is not under warranty and at present is essential to work - I can't do without it to get the keyboard looked at.

Fortunately I found a forum describing how to disable a key and remap it. The process is quite simple:

xmodmap -pke | grep "= *Alt"

Will give me the current mapping of the Alt key:

keycode  64 = Alt_L Meta_L Alt_L Meta_L

Opening a file in ~ called .Xmodmap and entering:

! Disable Alt key
keycode  64 = NoSymbol NoSymbol NoSymbol NoSymbol
! Enable Alt key
!keycode  64 = Alt_L Meta_L Alt_L Meta_L

Loading this into an existing X session is as simple as entering xmodmap .Xmodmap in terminal.

According to the forum post, not yet tested, logging out and back in will give me the option of permanently loading this default. It is also quite easy to see from this, or the xmodmap -pke command, how to remap another key to function as Alt, presumably one which is not accidentally triggered as my Alt key is.

I will report as to whether this actually fixes the issue, but could be useful for anyone experiencing hardware keyboard problems.

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  • I'm happy that you found a possible software solution. But I don't understand how the disabling of the left Alt key solved this, since you didn't say that the problem comes when you press it, and you also will need to block e.g. the "j" key, since the keylogger detected that one pressed too. Remapping the "j" doesn't seem viable to me.
    – falconer
    Feb 6, 2014 at 12:37
  • I'm no more knowledgeable in the situation, however I am assuming there was never a "j" keypress - just like the <E-71> key (which is one of the Fn keys) I think the keylogger (so whichever level that runs at) was receiving a confusing byte stream and just interpreted it. If I view the keylog files there are occasional really weird Unicode characters coming through, characters which definitely aren't on my keyboard. So it appears even there, there is some level of interpretation.
    – M1ke
    Feb 7, 2014 at 8:41

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