<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_RESOLVED bz_closed" title="RESOLVED FIXED - Ksnapshot (KDE) broken when using xf86-video-intel-2.99.916 + DRI3" href="https://bugs.freedesktop.org/show_bug.cgi?id=90836#c12">Comment # 12</a> on <a class="bz_bug_link bz_status_RESOLVED bz_closed" title="RESOLVED FIXED - Ksnapshot (KDE) broken when using xf86-video-intel-2.99.916 + DRI3" href="https://bugs.freedesktop.org/show_bug.cgi?id=90836">bug 90836</a> from <a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> Chris Wilson</a> <pre>(In reply to Loïc Yhuel from <a href="show_bug.cgi?id=90836#c11">comment #11</a>) > (In reply to Chris Wilson from <a href="show_bug.cgi?id=90836#c9">comment #9</a>) > Great, I can confirm the issue is fixed :) > > (In reply to Chris Wilson from <a href="show_bug.cgi?id=90836#c8">comment #8</a>) > > (In reply to Loïc Yhuel from <a href="show_bug.cgi?id=90836#c5">comment #5</a>) > > > (In reply to Chris Wilson from <a href="show_bug.cgi?id=90836#c4">comment #4</a>) > > > > Let's narrow down the reproduction steps then. How do you have kwin > > > > configured? > > > Compositing type : OpenGL 2.0 > > > Tearing Prevention : Full scene repaints > > > IIRC with this config and DRI3, kwin uses the GLX_EXT_buffer_age extension > > > (this is why I enable DRI3, else I have to choose between tear-free and > > > performance when I use two screens). > > > > Note that there a few caveats here. GLX_EXT_buffer_age in the client without > > support in mesa means that damage is not propagated back to the display > > server so that if you are using vnc, or udl, or something else like that it > > only sees full screen repaints and is so much slower than expected. > With Wayland, there would be EGL_EXT_swap_buffers_with_damage, I guess > something like this could be useful on GLX. And even trivial to implement. > > The other caveat is that DRI3 does not support single CRTC flipping like > > DRI2. That is you cannot have a single fullscreen application on one CRTC > > updating independently with the second screen (e.g. having a game/video on > > the primary monitor whilst reading email on the second). In this case DRI3 > > forces both screens to flip (and the compositor to repaint as required to > > correct damage), whereas ideally we would only update the single active CRTC > > and not touch the idle CRTC/buffer at all. > I don't think kwin supports flipping a single CRTC, else I wouldn't see any > performance difference in animations on the primary monitor when I plug the > second one. All that is required is for the compositor to unredirect the single-monitor "fullscreen" app. > Anyway, I need to set kwin to "full scene repaints" to avoid tearing, with > DRI3 it does in fact partial repaints using GLX_EXT_buffer_age, which is > faster than real full screen repaints with DRI2. Yes. As above, GLX_EXT_buffer_age can easily be done with DRI2 as well. I am just warning that GLX_EXT_buffer_age without a "GLX_MESA_swap_with_damage" extension has performance issues with PRIME setups or other extended desktop techniques(like VNC, screen capture).</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> <li>You are on the CC list for the bug.</li> <li>You are the assignee for the bug.</li> </ul> </body> </html>