Most recent kernel where this bug did not occur: 2.6.13.1 Distribution: Using Vanilla kernel, not stack. (ArchLinux) Hardware Environment: Asus M2400N, Centrino, Intel 855GM Software Environment: Linux/X.org/KDE Problem Description: GLX seems to be buggy. glxgears work flawlessly. glxinfo says direct rendering is on. However, OpenGL screensavers and apps either fail immediately, or produce a strange output, using only the upper part of the screen. Some of them segmentation faulted soon afterwards. Xinerama does not work any more. The double-headed layout cannot be used any more. An attempt to load X with double-headed layout results in blocking the chipset and the machine has to be rebooted to make X work again. Steps to reproduce: Launch X with KDE or Gnome and try some GL screensavers like Euphoria. Try startx with a double-headed layout or Xinerama turned on.
Exactly the same problem in 2.6.14.3.
you didn't upgrade X.org by any chance at some point, or does going back to 2.6.13.1 work with your current X setup? do you get direct rendering with 2.6.13.1?
Please reopen this bug if: - it is still present in kernel 2.6.16 and - you can provide the requested information.