Upgrading to 10.04? Might need to fix your display settings.

Call me an "early adopter", but I love playing with bleeding edge tech (when I have the cash :) even though it might cause a few buggy issues.

As such I was excited when Ubuntu 10.04 LTS was released just over a week ago. After installing the latest Karmic upgrades, I was presented with a friendly request to upgrade to 10.04 and decided to take it. And as always for Linux, the monetary cost isn't something I need to worry about :).

The Install Process

Installing over my Karmic install was fairly painless, but slow. It had to download about 2.5GB, which surprised me since the install CD's themselves are usually only around 700 MB. The download proceeded smoothly and after a few hours the install began. Again, there wasn't a heck of lot of user interaction on my part, just a few dialogs I needed to answer. After an hour or two more, I was prompted for a reboot to continue.

What the....?

Not sure I was quite prepared for what came next. As you might have seen before in my blog, I have a rather customized Gnome desktop, including a custom Xorg.conf file for extended displays. Upon rebooting, my entire desktop was...rather messed up. It's hard to describe, but the desktop seemed to be flipped 180 degrees, and the icons themselves were inverted. The entire desktop was also completely unresponsive. I couldn't click anything, nor would the keyboard or any of my short cuts respond!


Very strange, though I had an inkling it had to with my various desktop modifications. A close up on the Gnome menu:

What next?

Strange looking, hmmm? That's what I thought. However, this isn't the first time I've totally borked my Gnome desktop, so I knew what I had to do to reset it. I restarted and used grub to enter recovery mode which allowed me to boot into a command line interface (Tip: You can also try CTRL-ALT-F1 to get to a command line).

I then gained root access with a sudo bash command, and made a backup folder. From there, a copied the following four folders: .gnome2, .gconf, .gconfd and .gnome_private into the backup folder (Tip: You can use cp -r to move directories and their contents recursively).

I then used rm -rf to remove each of the folders (Don't do this as root from your / directory lest you delete your entire file system!)

Upon rebooting, Ubuntu decided it needed to do a disk check. Considering my last few hard reboots, this was expected:


After it was finished (~20 minutes), I booted into Gnome. My customized desktop was gone *but* everything was still oddly "inverted":



Still borked, apparently. The only other thing I could think of that might be causing such an odd issue is my custom Xorg.conf file, as these haven't officially been in Ubuntu for a while.

So I booted back into the terminal and removed it. And voila! I was presented with:


First thoughts on 10.04

As Bender would say, we're back baby! I then tried restoring my old Gnome settings from the backup (with the removed Xorg.conf, after backing up the current settings first), though this caused my Gnome to freeze on restart, so I put the old desktop back. Still, if you run into a similar issue, I recommend simply trying to remove your Xorg.conf first before resetting Gnome. I'll spend some time with the new Gnome theme before I decide how I want to customize it. So far it's pretty spiffy, if odd looking, not sure if I'll get used to the window controls being on the left side of the screen! No problems with my wi-fi, connected with no issues. My sound isn't working, though I have yet to figure out why, and I'll need to figure out how to bring back my extended display, such is the price you occasionally pay for trying out the latest and greatest. Still, the OS itself seems solid enough though (blazing fast on this outdated hardware!), and I look forward to playing with it more. Hope this post gives a hand to any others who run into the odd display issue I did!

Exploiting Kernel Null Dereferences

From the Ksplice blog comes a fantastic article about Exploiting NULL references in a kernel module to gain root access (or more...) over a system. It's a fantastically written piece, and easy to understand even for non-guru hackers. I recommended taking a few moments out to giving it a read!

Check it out here:

http://blog.ksplice.com/2010/04/exploiting-kernel-null-dereferences/

Extending your desktop to TV with Karmic Koala

Introduction

Ever since I've been using Ubuntu on my original laptop, I've been having great fun poking and prodding with its configuration, getting it to do some pretty fantastic things! My eventual goal is to turn this machine into a full fledged Linux-based HTPC (Home Theatre PC), and have been working on the project on and off to achieve that goal.

I don't have a high definition television, but the laptop comes equipped with a S-video out port, perfect for connecting the PC to my standard definition television. When I used to run openSuse, I had the proprietary ATI drivers installed and could use aticonfig to turn the extended desktop on and off.

Problems

Since switching to Karmic, I haven't quite been able to get this to work. The ATI drivers don't come installed by default, and they aren't open source anyway. I did make an attempt to install the drivers, but the OS seemed to ignore them and continue to use the open source drivers. I didn't want them unless necessary anyway, but the question remained: how to configure extended desktop without ATI config?

...and solutions!

The answer lies in the X Resize and Rotate Extension (RandR), or xrandr. If you run xrandr from Terminal, you should see something that looks like this:

Screen 0: minimum 320 x 200, current 1280 x 800, maximum 1280 x 1280
VGA-0 disconnected (normal left inverted right x axis y axis)
LVDS connected 1280x800+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
1280x800 59.9*+
1280x720 59.9
1152x768 59.8
1024x768 60.0 59.9
800x600 60.3 59.9
640x480 59.9 59.4

On my laptop, LVDS refers to the LCD screen. Listed there are a number of possible resolutions and screen refresh rates.

To activate your S-video out (or VGA), you'll need to add a display mode for it. Use the addmode function of xrandr for this:

xrandr --addmode S-video 800x600

In this case, I want to set an S-video out mode of 800x600 resolution. You should then see the mode if you run xrandr again:

S-video disconnected (normal left inverted right x axis y axis)
800x600 60.3

In order to actually use the S-video out, there are a number of options. The simplest is merely to activate it:

xrandr --output S-video --mode 800x600

But not quite...

This'll clone the desktop onto the S-video out. Unfortunately, since the LCD is running at 1280x800, you'll only see the top-left 800x600 pixels of your LCD display. This isn't particularly useful now is it? You can use the --pos YYYxZZZ option (e.g. --pos 100x100) option to move the output display around, but you'll still always be missing some of the screen.

Unfortunately, it was at this point that I hit a road block. I could clone the output, and move it around, but not get a dedicated output for the S-video out. What I decided to to was alter the command a little, I would turn off the LCD display, set the resolution to 800x600, then send it via the S-video:

xrandr --output LVDS --off --output S-video --mode 800x600

Now, I could have either a 1280x800 desktop on my LCD, or an 800x600 desktop on the TV. Not exactly what I wanted, but still sufficient for watching movies, videos, and even using the desktop on the TV.

Eventually, I realized what had to be done in order to extend the desktop.

1. Make the "virtual desktop" (amount of screen area) bigger
2. Use the --pos command to move the S-video output to the right of the LCD desktop.

xrandr has a --fb command for increasing the size of the "Frame Buffer" (the virtual desktop size). Alas, everytime I would try to change it, I'd get an error like this:

xrandr: screen cannot be larger than 1280x1280

Xorg.conf

Doing some searching, it seems the best advice was to configure the virtual desktop size in the Xorg.conf file (so the virtual screen size would be set while X server was starting). But hold on a moment...Ubuntu did away with Xorg.conf files in version 9.10! What to do? I made a few attempts at writing an Xorg.conf file by hand, but was always missing something causing my machine to reboot in "Low Graphics Mode". And my searches for changing the frame buffer without an xorg.conf, including a post on the Ubuntu forums, revealed no results.

Luckily, I found a post today on how to generate an xorg.conf from your current configuration. Essentially:

1. Reboot. When in grub, select to boot in recovery mode.
2. After logging in to a command prompt, run:

sudo Xorg -configure

3. This will create a xorg.conf.new file for you, likely in your home directory.
4. As root, copy this file into your /etc/X11/ folder (remember: back up the old one if there's already one there!)
5. Rename it to xorg.conf
6. Open your favorite editor (you can run startx now and do this from X Windows if you don't want to from the command line)
7. Find the "screen" module.
8. You'll see listed a number of display sections like so:

SubSection "Display"
Viewport 0 0
Depth 24
EndSubSection

To the most common ones (or even just the ones you'll use), add the following line:

Virtual 2080 800

9. Save, and restart.

Upon running xrandr at a command line now, you should see your virtual desktop has changed:

Screen 0: minimum 320 x 200, current 1280 x 800, maximum 2080 x 800.

You can now use the --pos to set your S-video output to 1280x0, which will put the video output to the right of the current desktop and Volia! Extended Desktop! You can now drag windows over to it (such as videos), full screen them, move them, even see your desktop effects!

Wrapping it up

To prevent having to use xrandr all the time, I made a few simple scripts for configuring the TV Out.

1. Go into your home folder. Create a folder called "Scripts".
2. We're going to make three scripts:
One for turning the TV out on in Extended Desktop, One for Clone Mode, and one for turning it off. First the deactivate script:
3. First, deactivate: In gedit (or another editor), paste the following into a text file:

xrandr --output LVDS --mode 1280x800 --output S-video --off

This'll deactivate the S-video and make sure your LCD is the main display. Save it as "Deactivate_TV_Out" or something alone those lines.

4. Now, activate in clone mode:

xrandr --addmode S-video 800x600
xrandr --output LVDS --off --output S-video --mode 800x600

and save as "Activate_TV_Out_Clone"

5. Finally, extended mode!

xrandr --addmode S-video 800x600
xrandr --output S-video --mode 800x600 --pos 1280x0

Call it "Activate_TV_Out_Extended"

6. For each file, right click and go to "Properties".

7. Under the permissions tab, click to allow for executing as program.

You can now click each of those to move back and forth between the various mode. Sometimes, you might have to deactivate the TV-out in order to activate it in a different mode. You can make shortcuts to these scripts, or as I did, set keyboard shortcuts:

1. Go to System->Preferences->Keyboard Shortcuts
2. Go to Add.
3. Give the shortcut a name "Activate_TV_Out_Extended", and point command to your script, e.g.
/home/jason/Scripts/Activate_TV_Out_Extended.
4. Do this for each of the other two scripts.

Make sure to use unassigned shortcuts, I used Ctrl-F1, F2 and F3 respectively. I am a bit unsure of including the "xrandr --addmode S-video 800x600" each time the script is run, but it doesn't seem to cause any problems. Without the mode being added, activating the TV out won't work. If I do find a way to keep the mode consistent, I'll update it here. Good luck, I hope others find these instructions useful (provided without any guarantees)! To end my post: something I haven't shown you yet on my blog: Jay's Desktop! I suppose it's about time =P.

Take care everyone!

New Virtual Box version fixes Gnome display issues

Happy Friday!

As a frequent user of virtual machines, I find myself quite impressed with their usefulness. Virtual machines allow you to emulate entire other operating systems within a host operating, called a virtual machine. You can even carry virtual machines with you from computer to computer and always have a custom system set up for your needs. Three common Virtual Machine platforms include Virtual Box, VMWare and Windows Virtual PC.

Due to it's freedom and flexibility, I tend to choose Virtual Box over option options. It has an extensive suite of features including seamless mode, mouse/keyboard integration, various device support and many more. It's also available for free under the personal use and evaluation license, and also has an open source edition.

One minor problem I've been having with Virtual Box involves the GNOME desktop environment used in many Linux distributions including Ubuntu.

The problem being that when one saves the VM execution state, and then resumes that state, the GNOME desktop graphic set (that is, its look and feel) appears to mysteriously change. Here's how it should look (click on the image to enlarge):

and after returning from a saved state:

As you can see, a number of icons have changed including the mail icon, terminal icon, network, sound, recycle bin. I would have to shut down GNOME and restart it (log back in) in order to restore their icons to the normal state.

I spent some time trying to figure out what was causing the odd issue, but to no avail. Nevertheless, I'm happy to report that upgrading to Virtual Box, 3.1.2, appears to fix this issue. Upon resuming from a saved state, the icons are no longer changed, or if they are, will immediately revert to the correct form! Fantastic!