Reland: Refactor DisplayGbm::generateConfigs

We should explicitly set EGL_SURFACE_TYPE to EGL_DONT_CARE.
Otherwise, it's default value is EGL_WINDOW_BIT. However,
on some platforms, only EGL_PBUFFER_BIT is supported.
In this case, no matching config is found. So mWindowSurface
and mPbufferSurface will be nullptr. That's why we see
the bot failed.

Bug: chromium:1105208
Change-Id: I8ee2487fd24bab86a5ec22fbe7b8ff68081bc15c
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2304429
Commit-Queue: Jiajia Qin <jiajia.qin@intel.com>
Reviewed-by: Geoff Lang <geofflang@chromium.org>

src/libANGLE/renderer/gl/egl/gbm/DisplayGbm.cpp

@@ -922,26 +922,48 @@ egl::Error DisplayGbm::makeCurrent(egl::Surface *drawSurface,
     return DisplayGL::makeCurrent(drawSurface, readSurface, context);
 }
 
+bool DisplayGbm::validateEglConfig(const EGLint *configAttribs)
+{
+    EGLint numConfigs;
+    if (!mEGL->chooseConfig(configAttribs, NULL, 0, &numConfigs))
+    {
+        ERR() << "eglChooseConfig failed with error " << egl::Error(mEGL->getError());
+        return false;
+    }
+    if (numConfigs == 0)
+    {
+        return false;
+    }
+    return true;
+}
+
 egl::ConfigSet DisplayGbm::generateConfigs()
 {
-    egl::ConfigSet configs;
+    // clang-format off
+    std::vector<EGLint> configAttribs8888 =
+    {
+        EGL_COLOR_BUFFER_TYPE, EGL_RGB_BUFFER,
+        EGL_SURFACE_TYPE, EGL_DONT_CARE,
+        EGL_CONFIG_CAVEAT, EGL_NONE,
+        EGL_CONFORMANT, EGL_DONT_CARE,
+        EGL_RENDERABLE_TYPE, EGL_DONT_CARE,
+        EGL_RED_SIZE, 8,
+        EGL_GREEN_SIZE, 8,
+        EGL_BLUE_SIZE, 8,
+        EGL_ALPHA_SIZE, 8,
+        EGL_BUFFER_SIZE, 32,
+        EGL_DEPTH_SIZE, 24,
+        EGL_NONE
+    };
+    // clang-format on
 
-    egl::Config config;
-    config.bufferSize         = 32;
-    config.redSize            = 8;
-    config.greenSize          = 8;
-    config.blueSize           = 8;
-    config.alphaSize          = 8;
-    config.depthSize          = 24;
-    config.stencilSize        = 8;
-    config.bindToTextureRGBA  = EGL_TRUE;
-    config.renderableType     = EGL_OPENGL_ES2_BIT;
-    config.surfaceType        = EGL_WINDOW_BIT | EGL_PBUFFER_BIT;
-    config.renderTargetFormat = GL_RGBA8;
-    config.depthStencilFormat = GL_DEPTH24_STENCIL8;
-
-    configs.add(config);
-    return configs;
+    if (!validateEglConfig(configAttribs8888.data()))
+    {
+        ERR() << "No suitable EGL configs found.";
+        return egl::ConfigSet();
+    }
+    mConfigAttribList = configAttribs8888;
+    return DisplayEGL::generateConfigs();
 }
 
 bool DisplayGbm::isValidNativeWindow(EGLNativeWindowType window) const

src/libANGLE/renderer/gl/egl/gbm/DisplayGbm.h

@@ -148,6 +148,7 @@ class DisplayGbm final : public DisplayEGL
                                 unsigned int tv_usec,
                                 void *data);
     void pageFlipHandler(unsigned int sequence, uint64_t tv);
+    bool validateEglConfig(const EGLint *configAttribs);
 
     gbm_device *mGBM;
     drmModeConnectorPtr mConnector;

src/tests/egl_tests/EGLSurfaceTest.cpp

@@ -180,6 +180,8 @@ class EGLSurfaceTest : public ANGLETest
                                            EGL_DONT_CARE,
                                            EGL_SAMPLE_BUFFERS,
                                            0,
+                                           EGL_SURFACE_TYPE,
+                                           EGL_DONT_CARE,
                                            EGL_NONE};
 
         EGLint configCount;
@@ -427,6 +429,7 @@ TEST_P(EGLSurfaceTest, ResizeWindow)
     initializeDisplay();
     initializeSurfaceWithDefaultConfig();
     initializeContext();
+    ANGLE_SKIP_TEST_IF(!mWindowSurface);
 
     eglMakeCurrent(mDisplay, mWindowSurface, mWindowSurface, mContext);
     eglSwapBuffers(mDisplay, mWindowSurface);
@@ -477,6 +480,7 @@ TEST_P(EGLSurfaceTest, ResizeWindowWithDraw)
     initializeDisplay();
     initializeSurfaceWithDefaultConfig();
     initializeContext();
+    ANGLE_SKIP_TEST_IF(!mWindowSurface);
 
     int size      = 64;
     EGLint height = 0;
@@ -566,6 +570,7 @@ TEST_P(EGLSurfaceTest, ResetNativeWindow)
 
     initializeSurfaceWithDefaultConfig();
     initializeContext();
+    ANGLE_SKIP_TEST_IF(!mWindowSurface);
 
     eglMakeCurrent(mDisplay, mWindowSurface, mWindowSurface, mContext);