199570 2019-07-08 04:34:37 -0700 [GTK] Blank web view when transitioning between hardware acceleration (composition) modes 2019-07-20 01:54:58 -0700 1 1 1 Unclassified WebKit WebKitGTK WebKit Local Build PC Linux NEW https://bugs.webkit.org/show_bug.cgi?id=199826 P2 Normal --- 1 mail webkit-unassigned bugs-noreply cgarcia mcatanzaro oldest_to_newest 1550788 0 mail 2019-07-08 04:34:37 -0700 WebKitGTK 2.24.2 I'm working on the WebKitGTK port of Next browser: https://next.atlas.engineer. (Mirror: https://github.com/atlas-engineer/next) When I switch "buffer" (or "tab") between 1 page displaying https://imdb.com and another displaying https://github.com, the github page is _very often_ blank (not always). If I open a new tab for github, it works. After a discussion with Michael Catanzaro, we presumed that the issue may lie in the transition in and out of accelerated composition mode. Indeed, if I start Next with WEBKIT_FORCE_COMPOSITING_MODE=1, the issue disappears. A work around would be to set it to "forced" with webkit_settings_set_hardware_acceleration_policy(), but what about systems that do not support hardware acceleration then? The problem occurs on master (for posterity: commit e13f5b9ecd232aa780b636a0c873fdccc1be6f0d). Could be related to https://bugs.webkit.org/show_bug.cgi?id=193224. 1550803 1 mcatanzaro 2019-07-08 07:37:21 -0700 It's not related to bug #193224 because PSON is not enabled in the 2.24 branch. 1553157 2 cgarcia 2019-07-16 03:24:51 -0700 I can't reproduce it with 2.24.2, but there are a lot more issues with current trunk, it only works with AC disabled. 1553161 3 cgarcia 2019-07-16 04:01:20 -0700 hmm, I guess I can't reproduce in 2.24 because AC is now forced in next. 1553168 4 cgarcia 2019-07-16 06:51:47 -0700 I've found the problem in trunk, but I can't reproduce it in trunk even when not forcing AC mode yet. 1553207 5 mail 2019-07-16 09:46:06 -0700 Indeed, as a workaround I'm forcing AC in Next. Force-disabling AC works too. Only "auto" triggers the issue. I'm not sure I understand the last comment: you found the problem, but it works with Next nonetheless? Is there anything I can do to help? 1553471 6 cgarcia 2019-07-17 03:12:26 -0700 I tried to reproduce the issue in current trunk patching next to not force AC mode, and I couldn't reproduce it. Neither with 2.24. 1553847 7 mail 2019-07-18 02:11:26 -0700 I'm running Next on Guix, if that can help reproducing the issue. (Guix can be installed on any GNU/Linux distro.) 1553848 8 cgarcia 2019-07-18 02:19:31 -0700 Wayland or X11? 1554478 9 mail 2019-07-20 01:54:58 -0700 X11.