[colug-432] Keybord input oddity... thoughts?
jeff.frontz at gmail.com
Sat Mar 31 16:09:37 EDT 2012
That sounds like a "key UP" event is getting lost. It's been a few
years since I've delved into the world of USB HID, but vaguely--
everything that happens on the keyboard is sent to the host as an
event. Key is pressed -- key down event is sent. Key is released --
key up event is sent. It's then up to the host to implement things
like shift, shift-lock, and.... repeating keys. So, if the host gets
a key down but never sees a corresponding key up, the host thinks
you're leaning on a key.
I can't remember how the X server works, but I suspect that it is
keeping a count for each key state-- key-down makes the count
increment; key-up makes the count decrement. So, no amount of
key-presses would clear it. You truly would need to pull your
keyboard (or otherwise cause it to disconnect from the USB) and
You can dork around with which interface the X server uses (kbd vs.
event) -- that might help a bit. I suspect, though, that your VM is
sending events to the wrong place every so often.
On Sat, Mar 31, 2012 at 1:14 PM, William Yang <wyang at gcfn.net> wrote:
> I'm running a dual boot Dell E6510 "desktop replacement" laptop, Ubuntu
> 10.04.4 and Win7 professional (both 64 bit). This component of my portable
> office is a near constant companion, giving me a big, high density screen
> and plenty of computing power to do whatever tasks I get asked to do. Of
> late, I'm spending a lot of time (>5 hours/day, every day) on this device.
> My split of Win vs Ubuntu differs based on the kind of work I'm doing, but
> for the past 2 months or so, it's been about 70% Windows to facilitate
> collaboration on documents with my clients.
> My problem... Occasionally on the Ubuntu side, the system *acts* like a
> keyboard key gets stuck, but no amount of tapping or adjustment of the
> keyboard is sufficient to resolve it until I restart the X server
> (unplugging the keyboard on my laptop requires a screwdriver to get at the
> plug; I've restarted the X server via SSH a couple of times, and that's
> been sufficient to stop the problem, but if I don't have another device on
> the same network that's handy, I have to reboot the box because no keyboard
> input works). It's a mild annoyance, but given how much time I spend on
> this thing, even mild annoyances are worth a moment's attention if it's
> straightforward to make them go away.
> Just from an anomoly identification standpoint, it's a little odd that I
> have *never* had a similar problem on the Win7 side. That makes me think
> it could be software, rather than hardware. A cursory search for bugs
> hasn't shown anything common... but I'm starting to wonder if there's an X
> input bug somewhere that I'm running into. Anyone else ever run into
> anything similar? Any suggestions as to approaches to resolve it?
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