Make xcb compile with X-less EGL implementations

On platforms like the Raspberry Pi the EGL implementation is not
compatible with X. This means that while EGL and Open GL ES can be enabled,
and will work fine with platform plugins like eglfs, EGL (and thus GL) should
be automatically disabled in xcb, otherwise a compilation error will occur
since xcb assumes the native handle types are the corresponding Xlib types.

Task-number: QTBUG-36551
Change-Id: I2cc4c558abb4b25d422a2c01da9b75b865ace402
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>

4 files changed, 93 insertions, 1 deletions

diff --git a/config.tests/qpa/egl-x11/egl-x11.cpp b/config.tests/qpa/egl-x11/egl-x11.cpp
new file mode 100644
index 0000000000..f5c2ae7260
--- /dev/null
+++ b/config.tests/qpa/egl-x11/egl-x11.cpp
@@ -0,0 +1,62 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the config.tests of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <EGL/egl.h>
+#include <xcb/xcb.h>
+#include <X11/Xlib.h>
+#include <X11/Xlib-xcb.h>
+
+// Check if EGL is compatible with X. Some EGL implementations, typically on
+// embedded devices, are not intended to be used together with X. EGL support
+// has to be disabled in plugins like xcb in this case since the native display,
+// window and pixmap types will be different than what an X-based platform
+// plugin would expect.
+
+int main(int, char **)
+{
+    Display *dpy = EGL_DEFAULT_DISPLAY;
+    EGLNativeDisplayType egldpy = XOpenDisplay("");
+    dpy = egldpy;
+    EGLNativeWindowType w = XCreateWindow(dpy, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
+    XDestroyWindow(dpy, w);
+    XCloseDisplay(dpy);
+    return 0;
+}
diff --git a/config.tests/qpa/egl-x11/egl-x11.pro b/config.tests/qpa/egl-x11/egl-x11.pro
new file mode 100644
index 0000000000..c4e94ca40c
--- /dev/null
+++ b/config.tests/qpa/egl-x11/egl-x11.pro
@@ -0,0 +1,12 @@
+SOURCES = egl-x11.cpp
+
+for(p, QMAKE_LIBDIR_EGL) {
+    exists($$p):LIBS += -L$$p
+}
+
+!isEmpty(QMAKE_INCDIR_EGL): INCLUDEPATH += $$QMAKE_INCDIR_EGL
+!isEmpty(QMAKE_LIBS_EGL): LIBS += $$QMAKE_LIBS_EGL
+
+CONFIG -= qt
+
+LIBS += -lxcb -lX11 -lX11-xcb
diff --git a/configure b/configure
index fee5885619..dc23bb4eb6 100755
--- a/configure
+++ b/configure
@@ -613,6 +613,7 @@ CFG_OPENVG_LC_INCLUDES=no
 CFG_OPENVG_SHIVA=auto
 CFG_OPENVG_ON_OPENGL=auto
 CFG_EGL=auto
+CFG_EGL_X=auto
 CFG_FONTCONFIG=auto
 CFG_FREETYPE=auto
 CFG_HARFBUZZ=no
@@ -1475,6 +1476,7 @@ while [ "$#" -gt 0 ]; do
     egl)
         if [ "$VAL" = "yes" ] || [ "$VAL" = "no" ]; then
             CFG_EGL="$VAL"
+            CFG_EGL_X="$VAL"
         else
             UNKNOWN_OPT=yes
         fi
@@ -5368,6 +5370,11 @@ if [ "$CFG_EGL" != "no" ]; then
     fi       # detect EGL support
     if compileTest qpa/egl "EGL" $QMAKE_CFLAGS_EGL $QMAKE_LIBS_EGL; then
         CFG_EGL=yes
+        if compileTest qpa/egl-x11 "EGL-X11" $QMAKE_CFLAGS_EGL $QMAKE_LIBS_EGL; then
+            CFG_EGL_X=yes
+        else
+            CFG_EGL_X=no
+        fi
     elif [ "$CFG_EGL" = "yes" ]; then
         echo " The EGL functionality test failed; EGL is required by some QPA plugins to manage contexts & surfaces."
         echo " You might need to modify the include and library search paths by editing"
@@ -5375,6 +5382,7 @@ if [ "$CFG_EGL" != "no" ]; then
         exit 1
     else
         CFG_EGL=no
+        CFG_EGL_X=no
     fi
 fi
 
@@ -5763,6 +5771,13 @@ else
     QCONFIG_FLAGS="$QCONFIG_FLAGS QT_NO_EGL"
 fi
 
+# enable egl on X
+if [ "$CFG_EGL_X" = "yes" ]; then
+    QT_CONFIG="$QT_CONFIG egl_x11"
+else
+    QCONFIG_FLAGS="$QCONFIG_FLAGS QT_NO_EGL_X11"
+fi
+
 # enable eglfs
 if [ "$CFG_EGLFS" = "yes" ]; then
     QT_CONFIG="$QT_CONFIG eglfs"
@@ -6788,6 +6803,9 @@ report_support "    getifaddrs ..........." "$CFG_GETIFADDRS"
 report_support "    IPv6 ifname .........." "$CFG_IPV6IFNAME"
 report_support "    OpenSSL .............." "$CFG_OPENSSL" yes "loading libraries at run-time" linked "linked to the libraries"
 report_support "  NIS ...................." "$CFG_NIS"
+report_support "  EGL ...................." "$CFG_EGL"
+report_support "  EGL on X ..............." "$CFG_EGL_X"
+report_support "  GLX ...................." "$CFG_XCB_GLX"
 report_support "  OpenGL ................." "$CFG_OPENGL" yes "Desktop OpenGL" es2 "OpenGL ES 2.x"
 report_support "  OpenVG ................." "$CFG_OPENVG-$CFG_OPENVG_SHIVA" yes-yes "ShivaVG" yes-no "native"
 report_support "  PCRE ..................." "$CFG_PCRE" yes "system library" qt "bundled copy"
diff --git a/src/plugins/platforms/xcb/xcb-plugin.pro b/src/plugins/platforms/xcb/xcb-plugin.pro
index 67f2d8a911..4727262f3f 100644
--- a/src/plugins/platforms/xcb/xcb-plugin.pro
+++ b/src/plugins/platforms/xcb/xcb-plugin.pro
@@ -90,7 +90,7 @@ contains(QT_CONFIG, opengl) {
             DEFINES += XCB_HAS_XCB_GLX
             LIBS += -lxcb-glx
         }
-    } else:contains(QT_CONFIG, egl) {
+    } else:contains(QT_CONFIG, egl):contains(QT_CONFIG, egl_x11) {
         DEFINES += XCB_USE_EGL
         CONFIG += egl
         HEADERS += qxcbeglsurface.h