Poll for the initial controller state when using DirectInput

This fixes getting a deflected axis as the first buffered input reading on a generic USB controller (G-Shark GS-GP702)

src/joystick/windows/SDL_dinputjoystick.c

@@ -849,6 +849,7 @@ int SDL_DINPUT_JoystickOpen(SDL_Joystick *joystick, JoyStick_DeviceData *joystic
     } else if (FAILED(result)) {
         return SetDIerror("IDirectInputDevice8::SetProperty", result);
     }
+    joystick->hwdata->first_update = SDL_TRUE;
 
     /* Poll and wait for initial device state to be populated */
     result = IDirectInputDevice8_Poll(joystick->hwdata->InputDevice);
@@ -1115,7 +1116,14 @@ void SDL_DINPUT_JoystickUpdate(SDL_Joystick *joystick)
         IDirectInputDevice8_Poll(joystick->hwdata->InputDevice);
     }
 
-    if (joystick->hwdata->buffered) {
+    if (joystick->hwdata->first_update) {
+        /* Poll to get the initial state of the joystick */
+        UpdateDINPUTJoystickState_Polled(joystick);
+        joystick->hwdata->first_update = SDL_FALSE;
+        return;
+    }
+
+    if (joystick->hwdata->buffered ) {
         UpdateDINPUTJoystickState_Buffered(joystick);
     } else {
         UpdateDINPUTJoystickState_Polled(joystick);

src/joystick/windows/SDL_windowsjoystick_c.h

@@ -76,6 +76,7 @@ struct joystick_hwdata
     LPDIRECTINPUTDEVICE8 InputDevice;
     DIDEVCAPS Capabilities;
     SDL_bool buffered;
+    SDL_bool first_update;
     input_t Inputs[MAX_INPUTS];
     int NumInputs;
     int NumSliders;