Slow KDE / Plasma on Intel Integrated Graphics?

June 25, 2009

Got a laptop with an Intel GMA? Is Alt+Tab slower than you would like? Does Plasma take forever to move or resize an applet? Maybe you didn’t think it could get better?

Try playing with the options in xorg.conf. This is a good starting place.

In my case lspci shows ‘Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller [8086:2a42]’, and putting

Option  “AccelMethod”   “UXA”

in /etc/X11/xorg.conf has improved things significantly. UXA acceleration has been disabled by default in Ubuntu because it caused problems for some people, but in my case enabling it has made everything snappier, and also gotten rid of the drawing artifacts I used to see.

It also caused suspend to stop working (assert in X upon waking), but a recent fix to xserver-xorg-video-intel takes care of that. Distros might have released an update by now, but if you’re using Kubuntu and can’t wait, you can grab the packages from this ppa.

Snappy plasma, working suspend, happy user.

Update: Here is a post with another trick, using the -graphicssystem raster option of Qt programs. It makes switching tabs in Konsole faster, and it does wonders for long lines in Kate!


The Magic SysRq Key

October 24, 2007

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One day I’ll stop apologizing for ignoring this blog for so long…

I’ve upgraded to Gutsy and it flies! I like Dolphin, the new file manager, and I’m sure it will get even better for KDE4.

There is one annoying glitch however. After waking up from STD (hibernate), all USB devices are dead. This has been fixed already in the latest kernel, and I’m just waiting for it to finally reach *Ubuntu repositories. Reading about the bug, I came across an interesting peculiarity of the Linux kernel. Sometimes I’m surprised at how much I don’t know ;)

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OK, here’s the deal. You can use the SysRq key to send requests directly to the Linux kernel. Why would you want to do that? Well, for starters, Linux may crash. WHAAAAT? Well, it may. Seldom, but it may. Especially if you mess around where you’re not supposed to :P

What can you ask the kernel to do using the SysRq key? Many things. One I find particularly useful is the Alt+SysRq+f. It kills the process which is using the most memory on your system. So when your system thrashes to death because of a runaway process, you don’t need to switch to the console (which may take ages) and use kill anymore. Just use the shortcut.

A few notes:

  • It’s Alt+SysRq and not just SysRq because the SysRq key shares a button with Print Screen, and without the Alt it would be interpreted as such.
  • IT DOESN’T WORK!! It may not work because you have a certain kernel option disabled. There’s not much you can do in that case, short of recompiling the kernel…
  • Be careful what you do. This is a gate directly into the kernel, and it allows you to do things like rebooting immediately without syncing disks, which could seriously screw up your file system.