<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - Wayland lacks cross-process synchronisation" href="https://bugs.freedesktop.org/show_bug.cgi?id=97353#c14">Comment # 14</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - Wayland lacks cross-process synchronisation" href="https://bugs.freedesktop.org/show_bug.cgi?id=97353">bug 97353</a> from <a class="email" href="mailto:tomek.bury@gmail.com" title="Tomek Bury <tomek.bury@gmail.com>"> Tomek Bury</a> <pre>(In reply to Daniel Stone from <a href="show_bug.cgi?id=97353#c13">comment #13</a>) > (In reply to Kristian Høgsberg from <a href="show_bug.cgi?id=97353#c12">comment #12</a>) > > Which compositor is this? QtWayland as of Qt 5.7. Back in the Qt 5.4 days (ish) that compositor was actually creating and destroying EGL images every frame, but that days are gone. The latest and greatest creates EGL image once and reuses it for the lifetime of a client. > > unrefs the EGLImages when a new wl_buffer is attached, but maybe there's > > some subtlety in the ref-counting there. I don't know, although Qt implementation also uses ref counting to decide when to end a wl_buffer_release. > I'd equally consider any compositor which doesn't do this to be broken. > Weston to the best of my knowledge (and a quick check) does destroy and > recreate. Again, I don't know. I didn't see anywhere such requirement or promise that EGL image wrapping wl_buffer is guaranteed to be destroyed before buffer release. If that was the case "release" would be a responsibility of a platform implementation, the same way the "attach" is. To my untrained eye wl_buffer_release() and eglImageDestroy() over 2 independent and asynchronous channels looks like asking for trou^H^H^H^H race condition. > You're very right that this should be documented better. I'm not sure if the > Khronos specs are the best place, or a document in the Wayland repository > itself. Can we take this bug as one request for explicit fencing support > (being actively pursued), and another one to document the EGL platform > requirements for both driver implementations and compositors? Thanks. Would you like me to create 2 dependent Mozilla tickets?</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> </ul> </body> </html>