As far as I have heard, dual booting (Ubuntu and Windows) in UEFI isn't very clean, and hence people prefer CSM when doing so. But, in case my laptop has Windows pre-installed in UEFI, I need to reinstall it to get it in CSM.
Now, my laptop's boot menu has an option of UEFI and CSM. What could this option mean? Does it mean I can dual boot without any hassles?