diff options
| -rw-r--r-- | src/plugins/platforms/xcb/qxcbconnection.cpp | 26 |
1 files changed, 21 insertions, 5 deletions
diff --git a/src/plugins/platforms/xcb/qxcbconnection.cpp b/src/plugins/platforms/xcb/qxcbconnection.cpp index d106473daa..3b3fcd0b49 100644 --- a/src/plugins/platforms/xcb/qxcbconnection.cpp +++ b/src/plugins/platforms/xcb/qxcbconnection.cpp @@ -231,9 +231,8 @@ void QXcbConnection::updateScreens(const xcb_randr_notify_event_t *event) QXcbIntegration::instance()->destroyScreen(screen); - // QTBUG-40174, QTBUG-42985: If there are no outputs, then there must be - // no QScreen instances; a Qt application can survive this situation, and - // start rendering again later when there is a screen again. + // QTBUG-40174, QTBUG-42985: If all screens are removed, wait + // and start rendering again later if a screen becomes available. } else if (!screen && output.connection == XCB_RANDR_CONNECTION_CONNECTED) { // New XRandR output is available and it's enabled @@ -293,13 +292,15 @@ void QXcbConnection::initializeScreens() { xcb_screen_iterator_t it = xcb_setup_roots_iterator(m_setup); int xcbScreenNumber = 0; // screen number in the xcb sense - QXcbScreen* primaryScreen = NULL; + QXcbScreen* primaryScreen = Q_NULLPTR; + xcb_screen_t *xcbScreen = Q_NULLPTR; + bool hasOutputs = false; while (it.rem) { // Each "screen" in xcb terminology is a virtual desktop, // potentially a collection of separate juxtaposed monitors. // But we want a separate QScreen for each output (e.g. DVI-I-1, VGA-1, etc.) // which will become virtual siblings. - xcb_screen_t *xcbScreen = it.data; + xcbScreen = it.data; QList<QPlatformScreen *> siblings; int outputCount = 0; int connectedOutputCount = 0; @@ -356,6 +357,7 @@ void QXcbConnection::initializeScreens() QXcbScreen *screen = createScreen(xcbScreenNumber, xcbScreen, outputs[i], output.data()); siblings << screen; ++connectedOutputCount; + hasOutputs = true; m_screens << screen; // There can be multiple outputs per screen, use either @@ -381,6 +383,20 @@ void QXcbConnection::initializeScreens() ++xcbScreenNumber; } // for each xcb screen + // If there's no randr extension, or there was some error above, or we found a + // screen which doesn't have outputs for some other reason (e.g. on VNC or ssh -X), + // but the dimensions are known anyway, and we don't already have any lingering + // (possibly disconnected) screens, then showing windows should be possible, + // so create one screen. (QTBUG-31389) + if (xcbScreen && !hasOutputs && xcbScreen->width_in_pixels > 0 && xcbScreen->height_in_pixels > 0 && m_screens.isEmpty()) { + QXcbScreen *screen = createScreen(0, xcbScreen, 0, Q_NULLPTR); + screen->setVirtualSiblings(QList<QPlatformScreen *>() << screen); + m_screens << screen; + primaryScreen = screen; + primaryScreen->setPrimary(true); + qCDebug(lcQpaScreen) << "found a screen with zero outputs" << screen; + } + // Ensure the primary screen is first in the list if (primaryScreen) { Q_ASSERT(!m_screens.isEmpty()); |