Older versions of KWin (<4.5) used to force indirect rendering. I forgot the main reason, but it might have to do with driver issues.
Indirect rendering does not resolve any driver issues. It actually adds new issues, removes features*, and makes everything slower. If this is KDE developers' policy, then everything is starting to make sense now.
* You can "remove" features simply by not using them.
Originally Posted by pingufunkybeat
s3tc *should* work with r300g if you install libtxc-dxtn, but only in 32 bits, and it's a shady legal situation.
It works on a 64-bit CPU with 64-bit apps too. For it to work with 32-bit apps as well (i.e. the most closed-source games), you have to compile libdrm + Mesa libs and drivers + libtxc-dxtn with the appropriate compile flags to get the 32-bit versions of everything.
Open drivers have a history of crashing when direct rendering is used, though. Open Arena had the same problem, as did many other games, back in the early days of r600c. We used to run the games using indirect rendering as a workaround.
I agree that documenting the issue and fixing the bugs is the right way to approach this, btw.
As far as I know, KWin runs by default some checks at the start of KDE and disable OpenGL rendering, thus use software rendering, if these checks fails. However, they added an option to the disable these checks, as sometimes, the checks failed but overall, the driver could very well do OpenGL compositing.
What you could try :
- Go into the System Settings, and go into where Desktop Effects are set up (in 4.5.X, it's in Desktop Effects). In the last tab, check the Disable Self-Test option or whatever it's called in english (I use french so don't know the exact translation).
- Enable the effects.
- In the Effects tab, unselect the Blur effect (it doesn't work anyway with ATI right now, neither with r300g nor with r600g, at least on my systems).
I sometimes have to fumble a bit with these settings (Enabling the effects fail with Blur but you cannot uncheck Blur before you tried at least once to enable the effects).
But with this, I don't have any special lag with Kwin and it works nicely, though I don't play games, so I cannot see exactly how much they're slowed down.
On ATI card with both radeon and fglrx driver, I have huge performance gain when I disable blur and oxygen animations (alt+f2 and type oxygen-settings and uncheck "enable animations" in widget style and window decorations).