Apr 4 2013

Raspberry Pi: Turning the monitor power on and off


Consolidating the info found here: http://www.raspberrypi.org/phpBB3/viewtopic.php?f=64&t=7570

Putting the monitor into power saving mode:

/opt/vc/bin/tvservice -p && /opt/vc/bin/tvservice -o

Turning the power back on:
/opt/vc/bin/tvservice -p && chvt 1 && chvt 7
Both “tvservice” and “chvt” need root permissions to work.  So you could use “sudo” or be logged in as root to run those commands, or you can make them suid:
chmod u+s /opt/vc/bin/tvservice
chmod u+s /bin/chvt
Note that suid binaries are generally considered a security risk since they run with root permissions.  Often there are ways to use the escalated privileges to run other commands as root.  So only make those binaries suid if you’re in an environment where it would be OK for anyone to have root privileges.
The information here was tested with a Raspberry Pi V2 connected to a DVI monitor through a $2 HDMI->DVI converter.

Oct 1 2012

VirtualBox and the Lenovo E420


I have a Lenovo Edge E420.  Overall I like it – it looks nice, I like it’s keyboard, it’s fast and was a reasonable deal when I bought.  However, after 6-8 months it totally died and I had to send it back for warranty repair.  It turns out that there is a known issue with it and they swapped the motherboard (and some other board related to its power supply) .  The whole deal took 4-5 days and if it had come back working, I would have been really happy about the experience.  (When I got it, it wanted me to login as IBM06 – whose password I could not guess.  I ended up having to reimage the machine which took some time and should not have been necessary.)  That’s another story I guess.

Which gets me to the point I wanted to record for my future googling self.  I went to reinstall Debian on VirtualBox on this machine, and no matter which image I used, it kept locking up when I’d hit the first screen where keyboard input was required.  I tried a number of different things but I couldn’t seem to get past this.  Eventually I stumbled across something in a google search – “make sure virtualization is enabled in the BIOS.”  Well, I hadn’t done that so I went and looked – BINGO.  The E420′s BIOS had Intel “Vt-D” disabled by default.  Once I turned on the virtualization features in the BIOS, installing Debian on VirtualBox was no problem.

May 31 2012

Can’t find the focusing crystal in Skyrim?


I searched and searched…  I looked at all of the Falmers and they did not have it.  Here’s a workaround.  Go to the console.  (Only available in the PC version.  Google it if you don’t know what this means.)

At the console do:

player.additem 0009f7a6

This will add the crystal to your inventory.  Now, to get Paratus Decimius to take you to the machine (and not just say to you repeatedly, “there’s no use talking unless you find the crystal”), do the following:

setstage mg06 40

You’ll want to do this inside the aerodome.  Hope this helps someone else get unstuck like it did for me.