Fixed screen flipping for devices where xres_virtual > xres

        /* flip buffer 180 degrees for devices with physicaly inverted screens */

        unsigned int i;

        unsigned int j;

        uint8_t tmp;

        for (i = 0; i < ((vi.xres_virtual * vi.yres)/2); i++) {

            for (j = 0; j < PIXEL_SIZE; j++) {

                tmp = gr_mem_surface.data[i * PIXEL_SIZE + j];

                gr_mem_surface.data[i * PIXEL_SIZE + j] = gr_mem_surface.data[(vi.xres_virtual * vi.yres * PIXEL_SIZE) - ((i+1) * PIXEL_SIZE) + j];

                gr_mem_surface.data[(vi.xres_virtual * vi.yres * PIXEL_SIZE) - ((i+1) * PIXEL_SIZE) + j] = tmp;

        for (i = 0; i < vi.yres; i++) {

            for (j = 0; j < vi.xres; j++) {

                memcpy(gr_framebuffer[gr_active_fb].data + (i * vi.xres_virtual + j) * PIXEL_SIZE,

                       gr_mem_surface.data + ((vi.yres - i - 1) * vi.xres_virtual + vi.xres - j - 1) * PIXEL_SIZE, PIXEL_SIZE);

            }

        }

#endif

#else

        /* copy data from the in-memory surface to the buffer we're about

         * to make active. */

        memcpy(gr_framebuffer[gr_active_fb].data, gr_mem_surface.data,

               vi.xres_virtual * vi.yres * PIXEL_SIZE);

#endif

        /* inform the display driver */

        set_active_framebuffer(gr_active_fb);