That’s a scary headline. Chances are, after seeing that, you might not care about the rest of this article. But hang on for a second: Have an Intel graphics chipset, or use an ATI graphics card (open-source drivers or not)? Then this image might be familiar to you:

If you don’t notice it right away, the glxgears window is below the other two. Ugly. This is a problem with the current X.Org stack using a rendering mode known as DRI1. I won’t go in to technical details of why this happens, but it all boils down to this: Using DRI1, 3D applications are given a space of the screen to draw into, and this is then sent directly to the display. That sounds somewhat logical, but when you throw in more fancy operations, such as Compiz and desktop effects, things get tricky. Keith Packard of Intel does a good job explaining this and other problems with X acceleration.

Keith mentions a golden combination that can be used right now. Fedora 11, arriving in one week, will include everything needed for a pleasant X experience. Ubuntu 9.04 does ship UXA, but it is not on by default due to stability issues at the time it was released. Instead, EXA is used, the same mode included with 8.10.

If you’re using Ubuntu 9.04 or another distribution with UXA support that is almost ready, there is a one-liner you can add to /etc/X11/xorg.conf. In the Device section, add Option “AccelMethod” “uxa” as it is below:

Section "Device"
	Identifier	"Configured Video Device"
	Option	"AccelMethod"	"uxa"
EndSection

Be prepared to revert the change later: without a newer kernel or X server, UXA mode has proven to be a little crashy. I’ve had good experiences while using at a 2.6.30 kernel, though I still do not use it for day-to-day computing. Even if you can’t get it to work for extended amounts of time yet, it still is nice to see this:

The glxgears test is positioned neatly in the background; you can see it through the semi-transparent terminal. And if that’s not enough proof that this works:

If you followed my recent video tutorial on enabling Ubuntu/GNOME’s Tracker search tool, you should now be enjoying the ability to search the files on your system.

During a recent upgrade to Ubuntu 9.04, which was recently released, I found that the Tracker search tool index had become corrupted. I tried to tell Tracker to rebuild the index, but experienced some weird issues.

In this quick tip, I’ll show you how to avoid this and other issues by deleting Tracker’s index and cache manually, so that it can start ‘from scratch’. Note that if you are having issues with tracker, it is worth trying to rebuild the index from the graphical interface first. This tip is a last resort if you need to clear everything out from scratch and start it again.

Tracker’s Files

According to the documentation, Tracker stores its files in the following locations:

• Configuration Files – ~/.config/tracker/tracker.cfg
• Data Files – ~/.local/share/tracker
• Index Cache – ~/.cache/tracker

If you’re happy with the settings you have, you may want to leave the configuration file intact, and just wipe out the data files and index cache.

Quit Tracker and Delete the Files

First of all, you need to go ahead and quit the Tracker application in the system tray.

Next, you must quit all processes of both trackerd and tracker-indexer, so open up a terminal and run these commands:

And finally, carefully delete the files listed above (excluding the config file, if you don’t think you need to clear that out as well).

So to recap, go ahead and delete the folders:

• ~/.local/share/tracker
• ~/.cache/tracker

and if you wish, the config files:

• ~/.config/tracker/tracker.cfg
• ~/.config/tracker/tracker-applet.cfg

To restart Tracker, I recommend that you log out and log back in so that trackerd and the system tray applet both restart properly. You should then be able to reconfigure it from the beginning as detailed in the original tutorial.

And that should be it – Tracker should rebuild itself from scratch. Useful to know for if things go wrong!

OpenOffice.org, while often criticised for its slightly antiquated interface, is arguably the most popular free software and open source office suite and in many cases, a good alternative to Microsoft's ubiquitous software system.

However, like many bits of software, it does have its annoyances. One of these is the 'help agent'. It is almost akin to the hated Office Assistant ('clippy') and pops up from time to time to tell you supposedly helpful things, like how it just corrected something you typed.

Note: today's tip is applicable to all systems where you can run OOo - Windows, Linux (and other Unix) and Mac OS X.

If the popup is really annoying you by being visually distracting, or if just gets on your nerves that it is popping up and trying far too hard to be helpful, it is easy to disable entirely.

To do so, go to Tools > Options and go to the General category.

On that screen, simply uncheck 'Help Agent', click OK, and the little light bulb should bug you no longer.

[via]