mart added a comment.
In https://phabricator.kde.org/D3777#71209, @davidedmundson wrote: > Oh! I think I now see why we have this bug. > > We get a disconnect then connect, which from Qt5.5 goes: > > Old Real Screen > Fake Screen > New Real Screen > > You never get any signals when you're going to or from the fake screen (by design), but implicitly that means we miss a real change. > > Is that the conclusion you had reached from debug? yes, I think what's happening, when the output switches the chain of events is QXcbConnection::destroyScreen() if (virtualDesktop->screens().count() == 1) { // If there are no other screens on the same virtual desktop, // then transform the physical screen into a fake screen. then the new output is enabled: QXcbConnection::updateScreens() ... } else if (!screen && output.connection == XCB_RANDR_CONNECTION_CONNECTED) { ... // Transform the fake screen into a physical screen screen->setOutput(output.output, outputInfo.data()); and in this, no primaryScreenChanged, not screenAdded/screenRemoved got emitted, because the only qscreen pointer was massaged into being fake, then real again, but the instance is always there. REPOSITORY R120 Plasma Workspace REVISION DETAIL https://phabricator.kde.org/D3777 EMAIL PREFERENCES https://phabricator.kde.org/settings/panel/emailpreferences/ To: mart, #plasma Cc: davidedmundson, plasma-devel, lesliezhai, ali-mohamed, jensreuterberg, abetts, sebas
