I can confirm that changing to the virtual terminal also stops working. This may be caused by the binary nvidia driver for
the GeForce 8600M GT graphics card in my PC. I am currently using version 295.49 of the driver but both installed
drivers have the fault. I have used Ubuntu on this PC for several years without this problem so this bug was
introduced with 12.04.
I have tried "$ sudo poweroff" from a terminal and it fails. Shutdown from an remote ssh login also fails. Currently I do not have
any safe way to shut down the system.
I can confirm that changing to the virtual terminal also stops working. This may be caused by the binary nvidia driver for
the GeForce 8600M GT graphics card in my PC. I am currently using version 295.49 of the driver but both installed
drivers have the fault. I have used Ubuntu on this PC for several years without this problem so this bug was
introduced with 12.04.
I have tried "$ sudo poweroff" from a terminal and it fails. Shutdown from an remote ssh login also fails. Currently I do not have
any safe way to shut down the system.