> The framebuffer that is displayed on the monitor is always in video card > memory. There is a piece of hardware (CRTC) that continuously pulls data > from the framebuffer and transmits it to the monitor.
So the framebuffer memory should normally be in the kernel (Perhaps in special cases could be mapped in the userspace?!). IIUC, XServer works on the app GUI data in the userspace and sends it to the kernel to finally arrive at the framebuffer. Correct? Does it use some kind of ioctl()?
