When I set compositing to opengl 3.1 i have no tearing and kwin is fast and slick. when i reboot i have some tearing and kwin is little bit slower, still fast. the problem is the tearing when scrolling or watching a full screen flash video. it seems that after the reboot the settings are changed back to opengl 2.0. I have an nvidia graphics card.
Steps to Reproduce:
1. Set compositing type to opengl 3.1, no tearing
after reboot there is again tearing.
the compositing type opengl 3.1 should be activated also after reboot.
*** Bug 323818 has been marked as a duplicate of this bug. ***
This has nothing to do with the GL version (if actually reset that's either due to HW support or a different bug) but a problem to reliably detect the availability of triple buffering. see dupe.
*** This bug has been marked as a duplicate of bug 322060 ***
well, what i dont get then why do i have a performance and a tearing difference? no tearing if i reset the opengl option, but the tearing is present again when i reboot.
(In reply to comment #3)
> well, what i dont get then why do i have a performance and a tearing
Did you read across the dupe?
In a nutshell: triple buffering is (likely) misdetected during login. Without either it or usleep yielding, swapping causes high cpu load, so it's forcefully deactivated.
W/o triple buffering, also chances raise to drop or miss a frame (because we stay in event processing as long as possible) and the event processing time naturally shortens as well -> seems slower.
-> Ensure to activate triple buffering and override the detection.