diff -ur qtbase-opensource-src-5.2.0/src/platformsupport/glxconvenience/qglxconvenience.cpp qtbase-opensource-src-5.2.0-allow-forcing-llvmpipe/src/platformsupport/glxconvenience/qglxconvenience.cpp

--- qtbase-opensource-src-5.2.0/src/platformsupport/glxconvenience/qglxconvenience.cpp	2013-12-08 18:09:47.000000000 +0100

+++ qtbase-opensource-src-5.2.0-allow-forcing-llvmpipe/src/platformsupport/glxconvenience/qglxconvenience.cpp	2014-01-29 17:41:57.000000000 +0100

@@ -116,6 +116,27 @@

 GLXFBConfig qglx_findConfig(Display *display, int screen , const QSurfaceFormat &format, int drawableBit)

 {

+    // Allow forcing LIBGL_ALWAYS_SOFTWARE for Qt 5 applications only.

+    // This is most useful with drivers that only support OpenGL 1.

+    // We need OpenGL 2, but the user probably doesn't want

+    // LIBGL_ALWAYS_SOFTWARE in OpenGL 1 apps.

+    static bool checkedForceSoftwareOpenGL = false;

+    static bool forceSoftwareOpenGL = false;

+    if (!checkedForceSoftwareOpenGL) {

+        // If LIBGL_ALWAYS_SOFTWARE is already set, don't mess with it.

+        // We want to unset LIBGL_ALWAYS_SOFTWARE at the end so it does not

+        // get inherited by other processes, of course only if it wasn't

+        // already set before.

+        if (!qEnvironmentVariableIsEmpty("QT_XCB_FORCE_SOFTWARE_OPENGL")

+            && !qEnvironmentVariableIsSet("LIBGL_ALWAYS_SOFTWARE"))

+            forceSoftwareOpenGL = true;

+

+        checkedForceSoftwareOpenGL = true;

+    }

+

+    if (forceSoftwareOpenGL)

+        qputenv("LIBGL_ALWAYS_SOFTWARE", QByteArrayLiteral("1"));

+

     bool reduced = true;

     GLXFBConfig chosenConfig = 0;

     QSurfaceFormat reducedFormat = format;

@@ -159,6 +180,10 @@

             reducedFormat = qglx_reduceSurfaceFormat(reducedFormat,&reduced);

     }

+    // unset LIBGL_ALWAYS_SOFTWARE now so other processes don't inherit it

+    if (forceSoftwareOpenGL)

+        qunsetenv("LIBGL_ALWAYS_SOFTWARE");

+

     return chosenConfig;

 }