gfx: wait for idle if rendering doesn't support explicit sync

src/gfx_apis/gl/egl/display.rs

@@ -129,6 +129,10 @@ impl EglDisplay {
                 .exts
                 .contains(KHR_FENCE_SYNC | KHR_WAIT_SYNC | ANDROID_NATIVE_FENCE_SYNC);
 
+            if !dpy.explicit_sync {
+                log::error!("Driver does not support explicit sync. Rendering will block.")
+            }
+
             Ok(Rc::new(dpy))
         }
     }

src/gfx_apis/gl/gl/sys.rs

@@ -66,7 +66,7 @@ dynload! {
         glClear: unsafe fn(mask: GLbitfield),
         glBlendFunc: unsafe fn(sfactor: GLenum, dfactor: GLenum),
         glClearColor: unsafe fn(red: GLfloat, green: GLfloat, blue: GLfloat, alpha: GLfloat),
-        glFlush: unsafe fn(),
+        glFinish: unsafe fn(),
 
         glReadnPixels: unsafe fn(
             x: GLint,

src/gfx_apis/gl/renderer/framebuffer.rs

@@ -86,7 +86,7 @@ impl Framebuffer {
             let fd = run_ops(self, ops);
             if fd.is_none() {
                 unsafe {
-                    (gles.glFlush)();
+                    (gles.glFinish)();
                 }
             }
             Ok(fd)

src/gfx_apis/vulkan/renderer.rs

@@ -747,6 +747,7 @@ impl VulkanRenderer {
             Ok(s) => Some(s),
             Err(e) => {
                 log::error!("Could not export sync file from fence: {}", ErrorFmt(e));
+                self.block();
                 None
             }
         };