With a default install of 11.4 (64bit) on a Dell Inspiron 1501, choosing the XFCE environment, it’s not possible to resume after hibernation. To hibernate, the green logout icon at the bottom corner of XFCE was clicked, and then “hibernate” was chosen from the dialog.
the progress indiciator after boot shows it is performing the resume, however it stops with a plain black screen and shows
it is possible to press CTRL+ALT+F1 to show a terminal, but returning to the graphical display shows the above “resuming…”.
A reboot is then required from the terminal to work again.
However, with a default 11.4 (64bit) install choosing Gnome instead, hibernation and resume works correctly.