Enhance the docs about window limitations and input devices

Task-number: QTRD-2421
Task-number: QTRD-2429
Change-Id: Ie47053f20d8587a84925d41e5a62cbd9ca88cbb4
Reviewed-by: Andy Nichols <andy.nichols@digia.com>

1 files changed, 22 insertions, 5 deletions

diff --git a/src/doc/src/b2qt.qdoc b/src/doc/src/b2qt.qdoc
index be8c8b0..341dfac 100644
--- a/src/doc/src/b2qt.qdoc
+++ b/src/doc/src/b2qt.qdoc
@@ -594,16 +594,23 @@
         <SDK_INSTALL_DIR>/Tools/b2qt/adb remount
     \endcode
 
-    In the \c{appcontroller.conf} file, the input devices are
+    In the \c{appcontroller.conf} file the input devices are
     specified by the lines similar to these:
     \code
         env=QT_QPA_GENERIC_PLUGINS=evdevtouch:/dev/input/event0
     \endcode
 
-    The mouse pointer can be turned on and off by removing or adding this line:
-    \code
-        env=QT_QPA_EGLFS_HIDECURSOR=1
-    \endcode
+    Usually there is no need to change this setting. USB input devices like
+    keyboards and mice are automatically recognized. The mouse pointer is shown
+    automatically if a mouse is connected.
+
+    Note however that hotplugging may not work, meaning that the input
+    devices, like keyboard and mouse, have to be connected at boot
+    time.
+
+    On some devices, for example the i.MX6 Sabre Lite, the touchscreen device is
+    specified explicitly in QT_QPA_GENERIC_PLUGINS. This is necessary because
+    the automatic device discovery would fail to find the touchscreen.
 
     \section1 Booting to a Custom Application
 
@@ -777,6 +784,16 @@
     Note that hotplugging does not currently work; any input device
     must be present at boot time to be recognized.
 
+    \section2 Application stops with \e{EGLFS: OpenGL windows cannot be mixed with others.}
+
+    In OpenGL and Qt Quick 2 applications there can only be one
+    fullscreen window existing at a time. Trying to create another
+    OpenGL window or trying to mix an OpenGL window with raster ones
+    will abort the application with the message shown above.
+
+    For raster (software rendered, e.g. QtWidget or QPainter-based
+    content) windows there is no such limitation.
+
     \section2 I cannot edit the contents of appcontroller.conf on the device
 
     The file system where this file is located may be mounted as read-only.