Alright, I'm not really sure what's going on here. My laptop is a Dell precision m4800 running Ubuntu 15.04 64bit. It boots fast, without any issues, and I am able to login and generally go about my business. The problem come when I try to log in to a virtual console, the login is flooded with "^[[26~" (no quotes), endlessly. To me, this indicated that a key (F14, I think is the key that escape code belongs to.) was being pressed down. So, back in my WM, I opened up a terminal emulator and ran evtest, checked each input device until I found one with a permanent keypress. This ended up being /dev/input/event4, "AT Translated Set 2 keyboard". Here is an excerpt:

Event: time 1435012752.408326, -------------- EV_SYN ------------
Event: time 1435012752.428534, type 4 (EV_MSC), code 4 (MSC_SCAN), value ae
Event: time 1435012752.428534, type 1 (EV_KEY), code 114 (KEY_VOLUMEDOWN), value 2
Event: time 1435012752.428534, -------------- EV_SYN ------------
Event: time 1435012752.546660, type 4 (EV_MSC), code 4 (MSC_SCAN), value ae
Event: time 1435012752.546660, type 1 (EV_KEY), code 114 (KEY_VOLUMEDOWN), value 2

...and so forth, endlessly. Now, I do not have a volumedown key anywhere on my computer/keyboard, so I am really confused. I removed my laptop keyboard while it was booted, and the events didn't stop. However, when I reboot without the keyboard, with an external keyboard plugged in, there is no flooding.

The only other odd thing going on is that my numlock light has been stuck on for the past week (since this flooding started happening), regardless of whether numlock is enabled. It has faded to less than half the brightness it was a week ago, and is half the brightness of the other keys on the media board (the media board is attached to the motherboard). I wonder if the media board.

Does anyone have any suggestions so far as to how to diagnose this or, more importantly, how to mitigate it so I can use the virtual consoles again? Also of interest here is that the volume down key is also being pressed in my windows partition.


This sounds like a hardware issue, since it is happening in both operating systems and you say that your numlock light is acting up as well.

Are you sure you don't have volume keys on your laptop? All pictures of your laptop that I've found would suggest that there are three in the top left where you say the media board is. If this is the case that daughterboard for the volume buttons and indicator lights is likely malfunctioning and needs to be replaced. Try disconnecting this board from the motherboard and booting either OS again, and if the key presses stop then it's definitely that board. If you're still under warranty have Dell fix it, otherwise you'll need to get it fixed elsewhere.

  • So, I was a total idiot and didn't see those buttons (I must have assumed they were pointless LEDs, subconsciously, who knows...). Pressing the volume down button solved that problem. My board that has the key state LEDs on it appears to be damaged, that's it. Thank you very much for your reply - I definitely could have gone another few months before noticing those :) – tworltler Jun 28 '15 at 6:32

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