Ubuntu

Keyboard input stalling

Asked by Philip Rademakers

Hi, I have a strange problem related to keyboard input in the gnome-terminal (I think it is only related to the gnome-terminal).
System boots fine. Login. Open gnome-terminal.
After some time, terminal cursor changes from blinking full suare into blinking open square (not filled).
Then keyboard in the gnome terminal is stalled.
Sometimes for a brief period of time, sometimes for 10 seconds or more.
I have been tail-ing various log files but I see no sign of any error.
System is Dell 1737 Studio laptop. Runs on a few startup services as possible.

At the same time when keyboard input disappears, I can't move any windows. Also window menus are not working.
I can continue to launch applications though.

I even get this pheonmenon after a full clean install of Ubuntu Karmic.

Any hints about how to further diagnose would be appreciated.

The only thing which I see when tail-ing syslog is this:

Nov 21 09:01:18 localhost wpa_supplicant[1165]: CTRL-EVENT-SCAN-RESULTS
Nov 21 09:01:58 localhost wpa_supplicant[1165]: CTRL-EVENT-SCAN-RESULTS
Nov 21 09:02:58 localhost wpa_supplicant[1165]: CTRL-EVENT-SCAN-RESULTS
Nov 21 09:04:18 localhost wpa_supplicant[1165]: CTRL-EVENT-SCAN-RESULTS
Nov 21 09:05:58 localhost wpa_supplicant[1165]: CTRL-EVENT-SCAN-RESULTS
Nov 21 09:07:58 localhost wpa_supplicant[1165]: CTRL-EVENT-SCAN-RESULTS
Nov 21 09:09:58 localhost wpa_supplicant[1165]: CTRL-EVENT-SCAN-RESULTS
Nov 21 09:11:58 localhost wpa_supplicant[1165]: CTRL-EVENT-SCAN-RESULTS
Nov 21 09:13:58 localhost wpa_supplicant[1165]: CTRL-EVENT-SCAN-RESULTS

Sometimes system seems to work OK for arbitrary amount of time (e.g. 10 minutes) and then it re-occurs.

What is strange as well is that the LED of one of the hotkeys on the portable is then on and hotkeys do not work.
When keyboard is working again, also hotkeys work.

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madmed (medbelh) said : 		#1

These errors are not related with the keyboard, its related with WPA-Supplicant http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=539915. Try with an external keyboard because it can be a hardware problem. Does it happen only when you open Terminal? also check the keyboard setting.

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Colin Ian King (colin-king) said : 		#2

Maybe running latencytop will show where there are system latencencies/hangs

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Philip Rademakers (philiprademakers) said : 		#3

Hmmm ... this is very weird.

Installed package latencytop, ran it. Then it said my kernel did not support latency measurements.
Changed kernel config, recompiled my kernel (it was custom kernel).
Restarted with new kernel. Ran latencytop.

Without doing any other change ... problem does not re-appear again.

I will keep it running like this and report any follow up.

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Philip Rademakers (philiprademakers) said : 		#4

Too fast ... problem does re-appear ;-(

But now only several minutes after a reboot (and I was not doing anything; just opened 1 terminal window).

Keyboard blocked for several minutes with very short slices of working keyboard time (could type 1 character; then blockage for 10 sec; then could type next character).

When keyboard is blocked, one of the LEDs of the hotkeys remains "on" (the button marked "<<"; I assume this is used if you are inside a sound player; which I am not)

What I saw in the latencytop window was "Waiting for CPU" for > 500 msec at one instance ... this looks very high to me. It was during Xorg process. But maybe I am not interpreting the LatencyTop output correctly.

And now, strangely enough, during the last 5 minutes keyboard continuously worked again.

Kernel 2.6.31, compiled with TIMER_FREQUENCY = 1000 Hz

Anything else I can do to further try and diagnose?

I have nothing special on my system, most startup scripts are turned off. Just running terminal, firefox and evolution. SYSV conf has bin-fmt, laptop-mode, nfs-kernel-server, preload, pulseaudio. That is all.

For the rest GNOME, pretty out-of-the-box install. Evolution-alarm-notifier, Keyring daemon, Settings daemon, Settings daemon helper, Indicator-applet, Network-manager, PolicyKit, PowerManager, Screensaver, Volume control.

Revision history for this message
Philip Rademakers (philiprademakers) said : 		#5

OK, I think I found the point of cause.

I disabled the gnome-power-manager (actually removed the package) and after reboot all seems OK.
The LED on the laptop hotkey does no longer light up and the hotkeys are still functioning.

Well, I can live without the gnome-power-manager I guess.

Root cause of course not so clear yet ...

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