Vulkan: Remove GL_BGRX8_ANGLEX from configurations

src/libANGLE/renderer/vulkan/xcb/DisplayVkXcb.cpp

@@ -85,7 +85,7 @@ SurfaceImpl *DisplayVkXcb::createWindowSurfaceVk(const egl::SurfaceState &state,
 
 egl::ConfigSet DisplayVkXcb::generateConfigs()
 {
-    constexpr GLenum kColorFormats[] = {GL_BGRA8_EXT, GL_BGRX8_ANGLEX};
+    constexpr GLenum kColorFormats[] = {GL_BGRA8_EXT};
     return egl_vk::GenerateConfigs(kColorFormats, egl_vk::kConfigDepthStencilFormats, this);
 }
 

src/tests/gl_tests/ClearTest.cpp

@@ -323,6 +323,15 @@ TEST_P(ClearTest, EmptyScissor)
 // Test clearing the RGB default framebuffer and verify that the alpha channel is not cleared
 TEST_P(ClearTestRGB, DefaultFramebufferRGB)
 {
+    // Some GPUs don't support RGB format default framebuffer,
+    // so skip if the back buffer has alpha bits.
+    EGLWindow *window          = getEGLWindow();
+    EGLDisplay display         = window->getDisplay();
+    EGLConfig config           = window->getConfig();
+    EGLint backbufferAlphaBits = 0;
+    eglGetConfigAttrib(display, config, EGL_ALPHA_SIZE, &backbufferAlphaBits);
+    ANGLE_SKIP_TEST_IF(backbufferAlphaBits != 0);
+
     glClearColor(0.25f, 0.5f, 0.5f, 0.5f);
     glClear(GL_COLOR_BUFFER_BIT);
     EXPECT_PIXEL_NEAR(0, 0, 64, 128, 128, 255, 1.0);