I've just got my new Lenovo ThinkPad X220 with Intel HD graphics (I'm not sure what the chip is) and I've installed Natty. Everything works great out of the box, except there are short pauses/freezes in the UI that randomly occur, they last less than 2 seconds, actions are still taking place in the background (like typing) when the UI un-freezes I can see the characters I've typed, the app I've clicked, loaded .

I can confirm that this is only happening with the new Natty 3D interface, I've tried 2D and the classic interface and there were no issues.

Googling this topic seems challenging as I can't relate the problem in keywords. And I keep getting results relating to full GUI freeze which I don't have.

This is troubling since I have Natty 3D running on older machines without any issues .

I wonder if anybody else have experienced this or came across this issue before.


  • Ahmad, have you installed all the updates for your machine? and if not can you please do that and report back if you are still encountering the problem.
    – scouser73
    Jun 22, 2011 at 15:50
  • Good thing you chose Lenovo, they certify their hardware. Unlike myself when the UI freezes it freezes until I SSH from a different machine to restart Compiz. Ubuntu is extremely buggy, all you can really do is wait for updates.
    – iridian
    Jun 22, 2011 at 17:51
  • yep, everything is up to date, it seems to get worse after coming back from suspend mode. Jun 23, 2011 at 0:23
  • I have noticed the following message in dmsg every time this happens: [ 1047.425428] [drm:i915_hangcheck_ring_idle] ERROR Hangcheck timer elapsed... blt ring idle [waiting on 377417, at 377417], missed IRQ? Jun 24, 2011 at 5:11

2 Answers 2


I've found the solution (and the source of the problem) it seems something to do with the intel driver, and apparently it has been fixed in newer kernels not yet released to 11.04.

the quick fix is to run the following:

echo 1 | sudo tee /sys/module/i915/parameters/semaphores

this temporarily fixed the problem for me, but the setting is reset after reboot. to set it permanently try the puting this option in /etc/default/grub

replace following line:



GRUB_CMDLINE_LINUX_DEFAULT="quiet splash i915.semaphores=1"

then update grub:

sudo update-grub

I had some sort of problem what I did to make it faster. I put mine swap to a lower priority this made my machine faster. It still it isn't as fast 10.10.

Check the value in terminal

cat /proc/sys/vm/swappiness

if this is 60 it's a bit high

To change this for one reboot

sudo sysctl vm.swappiness=10

Make it permantent:

gksudo gedit /etc/sysctl.conf

enter in text file at the bottom or if it's in the text file change it.


save and reboot

Hope this works you can have a look here

  • I figured the source of the problem (check the answer) but I'm going to try that to see if I can speed up my system even more ... all my Ubuntu machines have swappiness set to 60 is that the default value? Jun 24, 2011 at 18:21
  • @Ahmad Nassri 60 is default this is good for a server not best for some desktops if you have a fast hard disk you can take a higher value for better performance.
    – Rens
    Jun 24, 2011 at 20:30

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