Get rid of that f..ng "permission denied" error when using -acpitable file=/.. option in libvirt XML guest definition file.

ABSTRACT:

This post relates to how to activate an OEM windows10 when it runs as a kvm guest controlled by libvirt, getting rid of that f..ng "permission denied" you
get using the qemu:arg ... -acpitable command line option within the libvirt XML guest definition file.

WHAT TO DO IF YOU ARE IN HURRY:

Grab your product key out of MSDM ACPI table.
Place your SLIC.bin file in /usr/share/seabios directory and have the XML line to point at it.
<qemu:arg value='-acpitable'/>
<qemu:arg value='file=/usr/share/seabios/SLIC.bin'/>

Run your guest, go to Windows and activate it using the product key you grabbed from MSDM.
Done.

DETAILS:

TAB key autocomplete not working in xfce4 (no file completion)

First I noticed that bash autocomplete (also known as "shell file completion") stopped working. Pressing TAB I only see the cursor to flash a little and got no filename or command expansion.

All relevant lines in .bashrc were in place and correct.

Then I noticed the TAB key was not working in any application (e.g. text editors, mail, ....): TAB was doing nothing. So it is obvious that autocomplete couldn't work as well.
So I assumed that by pressing the TAB the applications receive a wrong code. As a counter-proof I've found that directly typing the TAB code (Ctrl-I) solves the problem. Remote ssh sessions worked fine.
Started to suspect an xfce4 wrong setting...

I've found the following solution:

How to test the TDK TBD420NR CCFL inverter

TDK TBD420NR inverter with some signal paths highlighted.

The TDK TBD420NR CCFL inverter is found in many laptop screens. I've found it in an HP Pavillon DV9500.

LCD screens with CCFL backlight are prone to failures and  you are often in doubt if it is an inverter or CCFL lamps failure.
So it is very useful to have a way to live check the inverter before ordering a new one just to discover that the failure is elsewhere.
I've found a way to live check the TDK TBD420NR.