Double buffering can be enabled by setting `STM32LTDC_USE_DOUBLEBUFFERING` to `GFXON`.
When double buffering is enabled, the 2nd LTDC layer cannot be used. While this limitation is easy to remove from a software perspective, there is little benefit in doing so. Double buffering requires, as the name implies, twice the memory. If the 2nd layer would be used together with double buffering strategy, a total of four full framebuffers would be required. Years of real-world experience shows that there's practically never enough memory bandwidth available to do this.
To use double buffering in an application, retrieve the two buffers via `gdispGetDisplay()`.
Whenever a buffer swap is necessary, use `gdispGControl(g, STM32LTDC_CONTROL_SHOW_BUFFER, NULL);` where `g` is the buffer to be shown.