I've got a fairly new Asus X550CC laptop with up to date xubuntu 14.04 on it. I'm using NVIDIA graphics drivers version 343.13. From day one I installed xubuntu on this machine I've been getting these random freezes. All graphics stop updating and the mouse pointer stops moving. Initially I thought the whole machine froze but then I realised if I swtich to a non-X desktop and back again (ctrl+alt+f1 followed by ctrl+alt+f7) things start working again.
Does anyone know what is causing this or how to debug what's going on? /var/log/Xorg.0.log shows something like this after the desktop change trick:
... ... [ 928.549] reporting 4 5 7 53 [ 928.585] reporting 4 5 7 53 [ 958.726] (II) NVIDIA(0): Setting mode "NULL" [ 958.727] (EE) NVIDIA(0): Failed to initiate mode change. [ 958.727] (EE) NVIDIA(0): Failed to complete mode change [ 958.742] (II) intel(G0): switch to mode email@example.com on LVDS1 using pipe 0, position (0, 0), rotation normal, reflection none [ 958.775] (--) synaptics: ETPS/2 Elantech Touchpad: touchpad found