Changes to driver workarounds.

- Force enable brokenFBOReadBack on non-Nokia v1.4 SGX drivers (as this is
  apparantly not fixed, except on the Nokia drivers)
- Add debug when workarounds are enabled to ease debugging

This fixes the following MeeGo bug:
https://bugs.meego.com/show_bug.cgi?id=5616

Merge-request: 1144
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>

1 files changed, 25 insertions, 2 deletions

diff --git a/src/opengl/qgl_egl.cpp b/src/opengl/qgl_egl.cpp
index 674d80d..d6b2d3b 100644
--- a/src/opengl/qgl_egl.cpp
+++ b/src/opengl/qgl_egl.cpp
@@ -39,6 +39,7 @@
 **
 ****************************************************************************/
 
+#include <QtCore/qdebug.h>
 #include <QtOpenGL/qgl.h>
 #include <QtOpenGL/qglpixelbuffer.h>
 #include "qgl_p.h"
@@ -195,6 +196,7 @@ void QGLContext::makeCurrent()
                 // PowerVR MBX/SGX chips needs to clear all buffers when starting to render
                 // a new frame, otherwise there will be a performance penalty to pay for
                 // each frame.
+                qDebug() << "Found SGX/MBX driver, enabling FullClearOnEveryFrame";
                 d->workaround_needsFullClearOnEveryFrame = true;
 
                 // Older PowerVR SGX drivers (like the one in the N900) have a
@@ -202,10 +204,31 @@ void QGLContext::makeCurrent()
                 // or GL_ALPHA texture bound to an FBO. The only way to
                 // identify that driver is to check the EGL version number for it.
                 const char *egl_version = eglQueryString(d->eglContext->display(), EGL_VERSION);
-                if (egl_version && strstr(egl_version, "1.3"))
+
+                if (egl_version && strstr(egl_version, "1.3")) {
+                    qDebug() << "Found v1.3 driver, enabling brokenFBOReadBack";
                     d->workaround_brokenFBOReadBack = true;
-                else if (egl_version && strstr(egl_version, "1.4"))
+                } else if (egl_version && strstr(egl_version, "1.4")) {
+                    qDebug() << "Found v1.4 driver, enabling brokenTexSubImage";
                     d->workaround_brokenTexSubImage = true;
+
+                    // this is a bit complicated; 1.4 version SGX drivers from
+                    // Nokia have fixed the brokenFBOReadBack problem, but
+                    // official drivers from TI haven't, meaning that things
+                    // like the beagleboard are broken unless we hack around it
+                    // - but at the same time, we want to not reduce performance
+                    // by not enabling this elsewhere.
+                    //
+                    // so, let's check for a Nokia-specific addon, and only
+                    // enable if it isn't present.
+                    // (see MeeGo bug #5616)
+                    if (!QEgl::hasExtension("EGL_NOK_image_shared")) {
+                        // no Nokia extension, this is probably a standard SGX
+                        // driver, so enable the workaround
+                        qDebug() << "Found non-Nokia v1.4 driver, enabling brokenFBOReadBack";
+                        d->workaround_brokenFBOReadBack = true;
+                    }
+                }
             }
         }
     }