On Tuesday 13 January 2015 23:06:40 Dmitry Volosnykh wrote: > Sean, thanks for your input. > > I have NVidia GeForce 9800M GTX, and VSync is enabled. Double-checked that. > Another enabled options: Allow Flipping and Use Conformant Texture > Clamping. Do not know what are they for... > > Regarding your question about monitor's refresh rate. Here is xrandr's > output: > $ xrandr > Screen 0: minimum 8 x 8, current 1680 x 1050, maximum 8192 x 8192 > DVI-D-0 disconnected (normal left inverted right x axis y axis) > LVDS-0 connected 1680x1050+0+0 (normal left inverted right x axis y axis) > 331mm x 207mm > 1680x1050 59.9*+ > DVI-D-1 disconnected (normal left inverted right x axis y axis) > HDMI-0 disconnected (normal left inverted right x axis y axis) > > I guess, it means runs on 60Hz refresh rate.
Hmm OK if that didn't work, can you try this trick. Try setting export __GL_YIELD="USLEEP" for your X environment. I have this set in /etc/profile.d/tearing.sh on Gentoo. Not sure where the correct place is on Ubuntu. If this is set when X starts this solves the tearing for me on nVidia when using a compositing window manager. Cheers, Sean > > On Tue, Jan 13, 2015 at 9:35 PM, Sean Harmer <sean.har...@kdab.com> wrote: > > On Tuesday 13 January 2015 17:02:40 Dmitry Volosnykh wrote: > > > I've tried to capture the issue: see http://youtu.be/KUNyk2YWBaY > > > The flickering is more obvious in this video since capturing software > > > affecting performance. When running application with no video recording > > > there's no visual artifacts for about 15 seconds. Then the top of the > > > > green > > > > > bar visually looks like be shifted leftwards by a small offset which > > > > holds > > > > > on form the moment of its appearance. The height of this 'cap' may > > > > slightly > > > > > increase over time. This issue reproduces constantly. > > > > Sounds like a lack of v-sync is causing tearing and over time the offset > > between the swapbuffers and screen refresh is changing. Is your monitor > > running > > at a standard refresh rate? > > > > Try forcing vsync in the control panel for your graphics card driver. At > > least > > nVidia provide an option for this. I'm not sure about AMD and Intel. > > > > Cheers, > > > > Sean > > -- > > Dr Sean Harmer | sean.har...@kdab.com | Managing Director UK > > Klarälvdalens Datakonsult AB, a KDAB Group company > > Tel. Sweden (HQ) +46-563-540090, USA +1-866-777-KDAB(5322) > > KDAB - Qt Experts - Platform-independent software solutions > > _______________________________________________ > > Interest mailing list > > Interest@qt-project.org > > http://lists.qt-project.org/mailman/listinfo/interest -- Dr Sean Harmer | sean.har...@kdab.com | Managing Director UK Klarälvdalens Datakonsult AB, a KDAB Group company Tel. Sweden (HQ) +46-563-540090, USA +1-866-777-KDAB(5322) KDAB - Qt Experts - Platform-independent software solutions _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest