Bug 178368

Summary:	Alt-tab, alt-f2 disables all keyboard input
Product:	[I don't know] kde	Reporter:	Tue Herlau <tue.herlau>
Component:	general	Assignee:	Unassigned bugs mailing-list <unassigned-bugs>
Status:	RESOLVED WORKSFORME
Severity:	normal	CC:	adaptee, julian, kde, matt
Priority:	NOR
Version:	unspecified
Target Milestone:	---
Platform:	Compiled Sources
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Tue Herlau 2008-12-21 15:13:10 UTC

Version: (using Devel)
OS: Linux
Installed from: Compiled sources

I have installed kde 4.2 beta 2 on kubuntu 8.10 using the standard method (backported packages from jaunty jacklope). Every time i eg press alt-tab, nothing happends except all keyboard input seems to be disabled (except ctrl-alt-backspace, ctrl-alt-(1..9) and similar xorg-related shortcuts). The pointer still works, but when interacting with applications it behaves as if the alt-key is pressed.
Besides this the desktop seems to behave normally, ie. no drawing problems, i can close and minimize applications using the pointer, etc. but the computer is, of course, completely unusable.
This is happening on an ibm thinkpad t60 with an ati x1300 which has had no problems like this with kde 4.0.* and kde 4.1.3. I have tried to remove .kde and .kderc and purged xorg and all related to the fglrx drivers and reinstalling using standard methods provided by kubuntu by no luck (because of this my xorg.conf file is completely trivial).
The keyboard layout is selected correctly in the control center, and the problem exist with and without desktop effects. If i type 'top' in the command line everything looks good, no funky new processes or an xorg which takes up 99% cpu or something like that.

The problem also exist if i press alt-f2 and/or try to interact with certain plasma components like using get hot stuff. The problem is 100% reproduceable on my system.

As far as i can tell everything else works as intended.

I think its very likely this is a question of a broken kubuntu package or something, but i hope this report might be of help anyway. kde 4.2 looks really good :-).

Comment 1 Julian Bäume 2009-01-30 21:37:11 UTC

I and at least 2 friends experienced something similar. On our systems this is not 100% reproduceable. It still happens with KDE4.2. All 3 of us have ThinkPads, too. 2xT43 and 1 R53. I use the radeon driver, so it doesn't seem to be fglrx related. I'm not sure if this also happened to me in KDE4.1, but IIRC it did.

I hope we can investigate the problem and fix it.

bye
julian

Comment 2 Julian Bäume 2009-01-30 22:28:09 UTC

(In reply to comment #1)
> All 3 of us haveThinkPads, too. 2xT43 and 1 R53.
> I use the radeon driver, so it doesn't seem to
> be fglrx related.
On correction here, it is a R51 and has got an Intel-graphics-chip. So most likely not an ATI relation.

Comment 3 Matt Hubert 2009-06-22 07:52:55 UTC

I can definitely confirm this bug. However, in my case it is intermittent. Every so often I will press Alt-Tab and the keyboard will disable. Usually (but not always) I can mash the keyboard for a while and eventually it comes back somehow, but that doesn't always work. It must be a KDE-related issue, because I can still Ctrl+Alt+F1..F9 to get to a different virtual terminal (and it works) and also Ctrl+Alt+Backspace as well (like Tue said).

This doesn't happen often and is hard to reproduce for me, but when it does, it is one of the most bizarre and arguably most severe bugs I've experienced in KDE. I as well am using a Thinkpad T60 but with an Intel 945GM. I'm using Kubuntu with KDE 4.2.90, but I've experienced this bug since at least 4.1.

This is a bad one.

Comment 4 Matt Hubert 2009-06-24 00:47:13 UTC

Having run into this bug about three times in the last day, I think I have figured out a way to reproduce it. If you alt+tab to a window and then alt+tab quickly back before it has loaded (choose a particularly slow window), your keyboard should be disabled. You may need to keep holding down alt the entire time.

Comment 5 Jekyll Wu 2011-12-11 18:53:49 UTC

This report is quite old and silent for a long time. I never met such problem so I will close it as 'WORKSFORME'.

Feel free to reopen the report if the problem still happens in recent version.