Bug 438363

A possibly relevant merge request was started @ https://invent.kde.org/plasma/kwin/-/merge_requests/1094

Thanks for bisecting. The fallback QPainter backend should probably be fixed, too...

Git commit 3d6659b0d7137e35f4a02bbc29787e5cf92bb414 by Xaver Hugl.
Committed on 10/06/2021 at 11:19.
Pushed by zamundaaa into branch 'master'.

platforms/drm: on NVidia do pageflips with QPainter

Otherwise it's just gonna display a static black screen

M  +3    -3    src/plugins/platforms/drm/drm_output.cpp

https://invent.kde.org/plasma/kwin/commit/3d6659b0d7137e35f4a02bbc29787e5cf92bb414

Git commit 40c485f2a6e3231f2398055987c5497270644e51 by Xaver Hugl.
Committed on 10/06/2021 at 13:06.
Pushed by zamundaaa into branch 'master'.

platforms/drm: fix EglStreamBackend init

M  +6    -9    src/plugins/platforms/drm/egl_stream_backend.cpp

https://invent.kde.org/plasma/kwin/commit/40c485f2a6e3231f2398055987c5497270644e51

Updated to latest git master that includes your changes. The changes do not solve the issue. I am still seeing a black screen only. This time even without a cursor being drawn. Attaching latest session log.

Created attachment 139294 [details]
Wayland session log (including fixes)

Git commit 6561b58d8164978e4b61d129aed6dba84e6a1eea by Xaver Hugl.
Committed on 13/06/2021 at 21:11.
Pushed by zamundaaa into branch 'Plasma/5.22'.

platforms/drm: on NVidia do pageflips with QPainter

Otherwise it's just gonna display a static black screen
(cherry picked from commit 3d6659b0d7137e35f4a02bbc29787e5cf92bb414)

M  +3    -3    src/plugins/platforms/drm/drm_output.cpp

https://invent.kde.org/plasma/kwin/commit/6561b58d8164978e4b61d129aed6dba84e6a1eea

The log looks like everything would be working correctly, it's using OpenGL rendering and pushing frames. I'm not sure what could be going on.

Does locally reverting 2742e5b422a543645467107c1f7e71e9f931a3b4 make a difference?

Reverting 2742e5b422a543645467107c1f7e71e9f931a3b4 alone does not help. Only in conjunction with reverting 40c485f2a6e3231f2398055987c5497270644e51 too I get a working wayland session again.

Could you test https://invent.kde.org/plasma/kwin/-/merge_requests/1105?

Tested the MR. I don't see a difference.

A possibly relevant merge request was started @ https://invent.kde.org/plasma/kwin/-/merge_requests/1107

This should really fix it as it just reverts the part that should be relevant here.

Can you please check the logs in .local/share/sddm/wayland-session.log? Maybe kwin prints something useful before quitting. Also, does kwin crash or simply quit?

Tested https://invent.kde.org/plasma/kwin/-/merge_requests/1107. I got it to work with one additional local change:

diff --git a/src/plugins/platforms/drm/egl_stream_backend.cpp b/src/plugins/platforms/drm/egl_stream_backend.cpp
index f2af3a3c9..ec0db19b7 100644
--- a/src/plugins/platforms/drm/egl_stream_backend.cpp
+++ b/src/plugins/platforms/drm/egl_stream_backend.cpp
@@ -283,7 +283,7 @@ bool EglStreamBackend::initRenderingContext()
 {
     initBufferConfigs();
 
-    if (!createContext() || !makeCurrent()) {
+    if (!createContext()) {
         return false;
     }
 
@@ -291,7 +291,8 @@ bool EglStreamBackend::initRenderingContext()
     for (DrmOutput *drmOutput : outputs) {
         addOutput(drmOutput);
     }
-    return true;
+
+    return makeCurrent();
 }
 
 bool EglStreamBackend::resetOutput(Output &o, DrmOutput *drmOutput)

@Simon that's very interesting. Does kwin start if you remove all setSurface() calls in egl_stream_backend.cpp?

Tested latest version of merge request without setSurface. Looks good. Thanks a lot!

Git commit 7552b530662da556a20ef32688b0be0043041b80 by Xaver Hugl.
Committed on 21/06/2021 at 12:49.
Pushed by zamundaaa into branch 'master'.

partially revert 2742e5b422a543645467107c1f7e71e9f931a3b4

It seems like without a surface creation of the scene fails somehow. At
least until the exact problem is solved, update outputs for EglStream
gpus before creating the EglStreamBackend.

M  +4    -0    src/plugins/platforms/drm/drm_backend.cpp
M  +2    -2    src/plugins/platforms/drm/egl_stream_backend.cpp

https://invent.kde.org/plasma/kwin/commit/7552b530662da556a20ef32688b0be0043041b80