I've recently installed Cyanogen Mod 9 on my HP Touchpad tablet, but I'm encountering problems when trying to access it from my Ubuntu laptop (Ubuntu 11.10, Gnome-Shell, Nautilus).
I've first tried accessing it via PTP as suggested here. Ubuntu will recognize the Touchpad as a digicam and only grant me access to two directories: "DCIM" and "Pictures".
I then tried accessing the tablet via MTP using this post on OMGUbuntu!. Ubuntu will connect to the tablet, but only grant me access to a folder named "Playlists".