I have searched the web prior to posting, and I can find several posts (in various *nix versions) about the NVidia
8400M having trouble with full frame flash, which means (notably) Youtube, back in 2010-2012.
In my searching I didn't find a definitive cure (just a load of "try this" style posts).
When watching youtube, if I go "fullscreen" it's very flickery to start with, then locks solid. Power sequence
is only way out.
Video card is essentially "good" (and quite fast); e.g. Stellarium runs at 59 f/s, fullscreen,
So - is this (old) problem still unsolved?
lshw -c video
description: VGA compatible controller
product: G86M [GeForce 8400M GS]
vendor: NVIDIA Corporation
physical id: 0
bus info: pci@0000:01:00.0
width: 64 bits
capabilities: pm msi pciexpress vga_controller bus_master cap_list rom
configuration: driver=nvidia latency=0
resources: irq:16 memory:fd000000-fdffffff memory:f4000000-f7ffffff memory:fa000000-fbffffff ioport:ef00(size=128) memory:fea00000-fea1ffff
dpkg -l | grep nvidia
nvidia-319-updates 319.60-0ubuntu1 amd64 NVIDIA binary Xorg driver, kernel module and VDPAU library
nvidia-settings-319-updates 319.60-0ubuntu1 amd64 Tool for configuring the NVIDIA graphics driver