diff --git a/data/shaders/tonemap.frag b/data/shaders/tonemap.frag
index d859bd492..f7b2d54b7 100644
--- a/data/shaders/tonemap.frag
+++ b/data/shaders/tonemap.frag
@@ -33,8 +33,6 @@ void main()
 
     // Uncharted2 tonemap with Auria's custom coefficients
     vec4 perChannel = (col * (6.9 * col + .5)) / (col * (5.2 * col + 1.7) + 0.06);
-    // Protect us from negative coefficient just in case...
-    perChannel = max(perChannel, vec4(0.));
     perChannel = pow(perChannel, vec4(2.2));
 
     vec2 inside = uv - 0.5;
diff --git a/data/shaders/utils/getLightFactor.frag b/data/shaders/utils/getLightFactor.frag
index c17a3ca8b..9bf4cdf58 100644
--- a/data/shaders/utils/getLightFactor.frag
+++ b/data/shaders/utils/getLightFactor.frag
@@ -14,6 +14,6 @@ vec3 getLightFactor(float specMapValue)
     vec3 DiffuseComponent = texture(DiffuseMap, tc).xyz;
     vec3 SpecularComponent = texture(SpecularMap, tc).xyz;
     float ao = texture(SSAO, tc).x;
-    vec3 tmp = DiffuseComponent + SpecularComponent * max(specMapValue, 0.);
+    vec3 tmp = DiffuseComponent + SpecularComponent * specMapValue;
     return tmp * ao;
 }
\ No newline at end of file
diff --git a/lib/irrlicht/source/Irrlicht/CIrrDeviceLinux.cpp b/lib/irrlicht/source/Irrlicht/CIrrDeviceLinux.cpp
index 00353a264..189f78aa3 100644
--- a/lib/irrlicht/source/Irrlicht/CIrrDeviceLinux.cpp
+++ b/lib/irrlicht/source/Irrlicht/CIrrDeviceLinux.cpp
@@ -499,6 +499,36 @@ void IrrPrintXGrabError(int grabResult, const c8 * grabCommand )
 static GLXContext getMeAGLContext(Display *display, GLXFBConfig glxFBConfig)
 {
 	GLXContext Context;
+  int compat43ctxdebug[] =
+		{
+			GLX_CONTEXT_MAJOR_VERSION_ARB, 4,
+			GLX_CONTEXT_MINOR_VERSION_ARB, 3,
+			GLX_CONTEXT_PROFILE_MASK_ARB, GLX_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB,
+			GLX_CONTEXT_FLAGS_ARB, GLX_CONTEXT_DEBUG_BIT_ARB,
+			None
+		};
+    int compat43ctx[] =
+    {
+        GLX_CONTEXT_MAJOR_VERSION_ARB, 4,
+        GLX_CONTEXT_MINOR_VERSION_ARB, 3,
+        GLX_CONTEXT_PROFILE_MASK_ARB, GLX_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB,
+        None
+    };
+	int core43ctxdebug[] =
+		{
+			GLX_CONTEXT_MAJOR_VERSION_ARB, 4,
+			GLX_CONTEXT_MINOR_VERSION_ARB, 3,
+			GLX_CONTEXT_PROFILE_MASK_ARB, GLX_CONTEXT_CORE_PROFILE_BIT_ARB,
+			GLX_CONTEXT_FLAGS_ARB, GLX_CONTEXT_DEBUG_BIT_ARB,
+			None
+		};
+    int core43ctx[] =
+    {
+        GLX_CONTEXT_MAJOR_VERSION_ARB, 4,
+        GLX_CONTEXT_MINOR_VERSION_ARB, 3,
+        GLX_CONTEXT_PROFILE_MASK_ARB, GLX_CONTEXT_CORE_PROFILE_BIT_ARB,
+        None
+    };
 	int compat33ctxdebug[] =
 		{
 			GLX_CONTEXT_MAJOR_VERSION_ARB, 3,
@@ -553,7 +583,19 @@ static GLXContext getMeAGLContext(Display *display, GLXFBConfig glxFBConfig)
 	PFNGLXCREATECONTEXTATTRIBSARBPROC glXCreateContextAttribsARB = 0;
 	glXCreateContextAttribsARB = (PFNGLXCREATECONTEXTATTRIBSARBPROC)
 						glXGetProcAddressARB( (const GLubyte *) "glXCreateContextAttribsARB" );
+  
+  // create compat 4.3 context (for proprietary drivers)
+    Context = glXCreateContextAttribsARB(display, glxFBConfig, 0, True, GLContextDebugBit ? compat43ctxdebug : compat43ctx);
+	if (!XErrorSignaled)
+		return Context;
 
+  XErrorSignaled = false;
+	// create core 4.3 context (for mesa)
+    Context = glXCreateContextAttribsARB(display, glxFBConfig, 0, True, GLContextDebugBit ? core43ctxdebug : core43ctx);
+	if (!XErrorSignaled)
+		return Context;
+
+	XErrorSignaled = false;
 	// create compat 3.3 context (for proprietary drivers)
     Context = glXCreateContextAttribsARB(display, glxFBConfig, 0, True, GLContextDebugBit ? compat33ctxdebug : compat33ctx);
 	if (!XErrorSignaled)
diff --git a/src/graphics/post_processing.cpp b/src/graphics/post_processing.cpp
index 42559bfda..90c7c85ba 100644
--- a/src/graphics/post_processing.cpp
+++ b/src/graphics/post_processing.cpp
@@ -335,6 +335,8 @@ void PostProcessing::renderGaussian6Blur(FrameBuffer &in_fbo, FrameBuffer &auxil
 void PostProcessing::renderGaussian17TapBlur(FrameBuffer &in_fbo, FrameBuffer &auxiliary)
 {
     assert(in_fbo.getWidth() == auxiliary.getWidth() && in_fbo.getHeight() == auxiliary.getHeight());
+    if (irr_driver->hasARBComputeShaders())
+        glMemoryBarrier(GL_FRAMEBUFFER_BARRIER_BIT);
     float inv_width = 1.0f / in_fbo.getWidth(), inv_height = 1.0f / in_fbo.getHeight();
     {
         if (!irr_driver->hasARBComputeShaders())
@@ -345,8 +347,10 @@ void PostProcessing::renderGaussian17TapBlur(FrameBuffer &in_fbo, FrameBuffer &a
         }
         else
         {
-
             glUseProgram(FullScreenShader::ComputeGaussian17TapHShader::getInstance()->Program);
+            glBindSampler(FullScreenShader::ComputeGaussian17TapHShader::getInstance()->TU_source, 0);
+            glBindSampler(FullScreenShader::ComputeGaussian17TapHShader::getInstance()->TU_depth, 0);
+            glBindSampler(FullScreenShader::ComputeGaussian17TapHShader::getInstance()->TU_dest, 0);
             glBindImageTexture(FullScreenShader::ComputeGaussian17TapHShader::getInstance()->TU_source, in_fbo.getRTT()[0], 0, false, 0, GL_READ_ONLY, GL_R16F);
             glBindImageTexture(FullScreenShader::ComputeGaussian17TapHShader::getInstance()->TU_depth, irr_driver->getFBO(FBO_LINEAR_DEPTH).getRTT()[0], 1, false, 0, GL_READ_ONLY, GL_R32F);
             glBindImageTexture(FullScreenShader::ComputeGaussian17TapHShader::getInstance()->TU_dest, auxiliary.getRTT()[0], 0, false, 0, GL_WRITE_ONLY, GL_R16F);
@@ -354,24 +358,35 @@ void PostProcessing::renderGaussian17TapBlur(FrameBuffer &in_fbo, FrameBuffer &a
             glDispatchCompute(in_fbo.getWidth() / 8, in_fbo.getHeight() / 8, 1);
         }
     }
+    if (irr_driver->hasARBComputeShaders())
+        glMemoryBarrier(GL_SHADER_IMAGE_ACCESS_BARRIER_BIT);
     {
+#ifdef WIN32
         if (!irr_driver->hasARBComputeShaders())
+#endif
         {
             in_fbo.Bind();
 
             FullScreenShader::Gaussian17TapVShader::getInstance()->SetTextureUnits(createVector<GLuint>(auxiliary.getRTT()[0], irr_driver->getFBO(FBO_LINEAR_DEPTH).getRTT()[0]));
             DrawFullScreenEffect<FullScreenShader::Gaussian17TapVShader>(core::vector2df(inv_width, inv_height));
         }
+#ifdef WIN32
         else
         {
             glUseProgram(FullScreenShader::ComputeGaussian17TapVShader::getInstance()->Program);
+            glBindSampler(FullScreenShader::ComputeGaussian17TapVShader::getInstance()->TU_source, 0);
+            glBindSampler(FullScreenShader::ComputeGaussian17TapVShader::getInstance()->TU_depth, 0);
+            glBindSampler(FullScreenShader::ComputeGaussian17TapVShader::getInstance()->TU_dest, 0);
             glBindImageTexture(FullScreenShader::ComputeGaussian17TapVShader::getInstance()->TU_source, auxiliary.getRTT()[0], 0, false, 0, GL_READ_ONLY, GL_R16F);
             glBindImageTexture(FullScreenShader::ComputeGaussian17TapVShader::getInstance()->TU_depth, irr_driver->getFBO(FBO_LINEAR_DEPTH).getRTT()[0], 1, false, 0, GL_READ_ONLY, GL_R32F);
             glBindImageTexture(FullScreenShader::ComputeGaussian17TapVShader::getInstance()->TU_dest, in_fbo.getRTT()[0], 0, false, 0, GL_WRITE_ONLY, GL_R16F);
             FullScreenShader::ComputeGaussian17TapVShader::getInstance()->setUniforms();
             glDispatchCompute(in_fbo.getWidth() / 8, in_fbo.getHeight() / 8, 1);
         }
+#endif
     }
+    if (irr_driver->hasARBComputeShaders())
+        glMemoryBarrier(GL_TEXTURE_FETCH_BARRIER_BIT);
 }
 
 void PostProcessing::renderPassThrough(GLuint tex)