Screen freezes on Kubuntu 12.04 beta 2

[geoaraujo]

Hello.
After the upgrade to 12.04 beta 2, my system sometimes freezes randomly and I'm forced to hard reset.
Is this a bug? Or beta issue? Is there a workaround?
Anyone facing the same?

[dibl]

my system sometimes freezes randomly

You say "system", but really it is video-only that is freezing. The OS continues to run underneath -- it is not frozen. The first thing to try is to just leave it alone for 5 or 10 minutes, and the congestion may clear.

and I'm forced to hard reset.

No, you are not forced. You should use the "Magic SysRq" combination:

Alt-SysRq R S E I U B

Hold down the Alt and the SysRq keys at the same time, and while holding them down press R, S, E, I, U, and B keys in slow sequence. This will shut down and restart the computer "gracefully", syncronizing open files and saving your filesystem from the destruction that can happen when you press the reset button.

While your system is running correctly, open a konsole window and enter "top" and then just let it stay open. When the "freeze" happens, take a look at that window and see what is the top process that is using all the resources?

Also, you can investige the logs under /var/log to find out what is using up the resources when the system appears to be frozen. Try turning off the nepomuk and strigi services.

[geoaraujo]

You say "system", but really it is video-only that is freezing. The OS continues to run underneath -- it is not frozen. The first thing to try is to just leave it alone for 5 or 10 minutes, and the congestion may clear.



No, you are not forced. You should use the "Magic SysRq" combination:

Alt-SysRq R S E I U B

Hold down the Alt and the SysRq keys at the same time, and while holding them down press R, S, E, I, U, and B keys in slow sequence. This will shut down and restart the computer "gracefully", syncronizing open files and saving your filesystem from the destruction that can happen when you press the reset button.

While your system is running correctly, open a konsole window and enter "top" and then just let it stay open. When the "freeze" happens, take a look at that window and see what is the top process that is using all the resources?

Also, you can investige the logs under /var/log to find out what is using up the resources when the system appears to be frozen. Try turning off the nepomuk and strigi services.

Thanks for your answer. I'll try if it happens again.
But, is this a beta bug/issue?

[Snowhog]

Thanks for your answer. I'll try if it happens again.
But, is this a beta bug/issue?

Until you can help us identify what the cause might be, that question cannot be answered. Do as dibl suggested. The next time you experience your system "freezing", tell us what process (from top) are identified as using the most resources.

[dibl]

But, is this a beta bug/issue?

It is a commonly reported observation on new Linux installations, and has been for many years. It could be a bug in a video driver, it could be a background service sucking resources that you could turn off, it could be other things. The basic problem is, the demand for CPU + graphics resources is exceeding the capacity of your system to fully and immediately respond, in its present configuration. As Snowhog says, if we can do some fault isolation, such as I suggested, then we can begin to narrow down the specific causal factor(s) on your system.

[dethadol]

I have experienced this problem 0n 11.10.

Whilst dibl's advice is right I have found an easier way, for me, to deal with this isssue.

When the screen freezes I hit Ctrl -- Esc this brings up the system monitor which I immediately close using the X button and the system is back to normal.

Interestingly if I have done something else, such as keyboard input, whilst the screen is frozen this action has been carried out and appears instantly once the screen is unstuck.

This might work for you

[Guest]

I will tell you my situation, you decide if it is appropriate. At one point my desktop started freezing randomly, other times the screen would go black. Opening a console was impossible since both the keyboard and mouse no longer worked, like I said frozen. I know the system kept working because I could access it from another machine and get stats on the situation but nothing to tell me what was causing it, it always froze due to different things I was doing. The one thing I did remember is that all the problems started about the time I enabled desktop effects so I decided to disable them. To my surprise every time I rebooted they were still enabled, I tried all combinations but they kept coming back (like the cat). My last resort was to manually edit the '/home/chris/.kde/share/config/kwinrc' file, and change the line 'Enabled=true' to 'Enabled=false'. Saved and restarted the system. So far so good. I hope this helps