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:

go to settings->settings editor;
select xfce4-keyboard-shortcuts on the left pane;
select xfwm4->custom on the right pane;
go down to the <Super>TAB entry.

You'll find it set to "Switch_window_key";
Just set "Value" to nothing (just delete the "Switch_window_key" string in it);
logout; login;
et voilà.

Hope this help!

For further info: See Xfce bug 10760

Emanuele.

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.

Material needed:
- cc power supply capable of 18V 3A;
- a trimmer 1Kohm;
- a multimeter (any kind);
- some wiring (of your choice); I also used a solder-less breadboard;
- a good CCFL lamp with a connector compatible with the inverter output socket.

First you need to get +4Volts out of the 18V available: connect the trimmer with external pins to +18 and GND respectively. Connect the multimeter to the central pin, turn the trimmer until you get 4volt (not critical, but no more than 5V not less than 2V) .

Connect the CCFL lamp to the inverter output socket.
To power the inverter up connect +18Volts and ground at red and blue circles respectively (see pic).
To enable it poke +4Volts to the yellow circle (it is close to the left of R14: it is the test point for the ENABLE signal).

TDK TBD420NR with connection points highlighted.

Et voilà, if the inverter is goods the lamp should lit.

Once you are sure the inverter is good you can replace the test lamp with your screen and test the backlight CCFLs as well.

Here is my fixture...

TDK TBD420NR test fixture.

Good luck with you inverter ;=))

Installing an HP OEM Windows 2012 R2 Essential server as KVM Guest

I have an HP Proliant DL385p Gen8 box together with a HP/OEM installation disk of Windows Server 2012 R2 Essential.
On the iron I've installed Ubuntu Server 12.04.5 64bit plus xfce 4.1 (horrible: avoid it!) and KVM latest version available in ubuntu repository at the time of this writing (Dec2014).
The windows server is going to run as a guest over KVM. I have plenty of configurations like this perfectly working where, however, the Windows software is not OEM..
Here, a little while after the windows server installation CD boots up in the guest, it stops with the following message:"This system is not a supported platform": the hardware platform must be an HP and the actual one is not. No way.

HP supports this scenario (http://h20564.www2.hp.com/hpsc/doc/public/display?docId=emr_na-c00970200) suggesting ways for the hypervisor to pass BIOS and System information from host hardware to guests. Unfortunately KVM is not included...
Reading the redhat documentation (https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Virtualization_Administration_Guide/sect-smbios-sys-info.html) helped in finding a solution:
First you need to dump the HP BIOS information by running the “dmidecode“ command, to retrieve the information you need:

# dmidecode 2.11
 SMBIOS 2.6 present.
 35 structures occupying 1145 bytes.
 Table at 0x000FB330.
Handle 0x0000, DMI type 0, 24 bytes
 BIOS Information
 Vendor: HP
 Version: A28
 Release Date: 07/12/2014
 ....
 Handle 0x0001, DMI type 1, 27 bytes
 System Information
 Manufacturer: HP
 Product Name: Proliant DL385p Gen8
 Version:
 Serial Number: 099999AB
 UUID: 1A3FD5918-FA32-56B3-8000-3A5C8B66F003
 Wake-up Type: Power Switch
 SKU Number: 947382-432
 Family:
 ...

Now just open your Guest XML file (in /etc/libvirt/qemu/) and, as per redhat instructions, into <os> tag add:

<smbios mode="sysinfo">

and then, somewhere into <domain> tag add this, with values from dmidecode output:

<sysinfo type='smbios'>
 <bios>
  <entry name='vendor'>HP</entry>
 </bios>
 <system>
  <entry name='manufacturer'>HP</entry>
  <entry name='product'>Proliant DL385p Gen8</entry>
  <entry name='serial'>099999AB</entry>
  <entry name='sku'>947382-432</entry>
  <entry name='UUID'>1A3FD5918-FA32-56B3-8000-3A5C8B66F003</entry>
 </system>
</sysinfo>

And that’s all, folks! Now just start your Guest and the Windows Server  installation should pass the HP hardware check. Please note that Windows 2008 didn't need the UUID field.