At our school, we’ve been running Fedora on most of the desktops since Fedora 8, but the one department that’s stuck with Windows is the accounting department, mainly because their software is Windows-only.  This has long been a problem because most of our infrastructure is built around Linux and we haven’t put nearly as much energy into making sure Windows systems are maintained properly.

Obviously, this led to problems that started out small, but grew until the systems were bordering on unusable.  When it reached the point that we were considering yet another reinstall of Windows, I suggested switching the accountants over to Fedora and having them use a virtual machine for the software that required the other OS.

It took a few days to get something that worked, and another week (including one very late night) to tie down the little glitches and get the virtual machine beyond just-usable to easy-to-use.

I started with VirtualBox, but there were a number of issues with stability, so I decided to take another look at QEMU.  I thought about using libvirt, but one of my requirements was that everything needed to run under the user’s permissions, so it turned out to be easier to run qemu-kvm directly.  I used SPICE and installed the guest agent, which gave us a far better experience with QEMU than the last time I used it for a desktop OS (which, granted, was over five years ago).

Most of my time was spent fixing problems inherent to Windows 7 itself, rather than the virtualization process.  It turns out that there are bugs in how it handles network printers, causing delays every time you want to print.  Oddly enough, the fix was pretty simple, but it took a while to figure it out.  There was also the bug where network drives aren’t mapped properly if the system boots so quickly that the network isn’t up in time, which was only fixable by using a batch file for mapping the network drives.

One change I made was to insist that we use throw-away snapshots for day-to-day work (the data is stored on a network drive) and only keep changes when we’re updating the accounting software.  This should help protect us from viruses and malware that can’t be easily removed.

The best part of all this is that the new accounting VM and the scripts necessary to start it are sitting in a network folder only accessible by the accountants.  This means that they can now do their work from any computer in the school, if necessary, while still protecting them.

And I’m no longer stuck keeping unmanaged Windows systems running.  What a way to close out the year!

Colorful Fireworks by 久留米市民(Kurume-Shimin) used under a CC BY-SA 3.0 unported license

One of the features my laptop comes with is Bluetooth, which I’ve found to be quite handy considering all the highly important uses I have for Bluetooth (using Bluetooth tethering on my phone when traveling, controlling my presentations with my phone, using a Wii-mote for playing SuperTuxKart portable Bluetooth controller with built-in accelerometer to analyze the consistency of the matrices used when rendering three-dimensional objects onto a two-dimensional field).

About three months ago, I started to run into problems. Not the easy kind of problem where “BUG: unable to handle kernel paging request at 0000ffffd15ea5e” brings the laptop to an abrupt stop, but instead the kind of problem that causes real trouble.

My Bluetooth module starts to randomly reset itself. I’ll be working merrily, trying to connect my phone or the… portable Bluetooth controller… and, halfway through the process, it will hang. Kernel logs show that the Bluetooth module has been unplugged from the USB bus and then reconnected. Which, when you think about it, makes a whole lot of sense, given that the Bluetooth module is built into the WiFi card which is screwed onto the motherboard.

When faced with kernel logs that boggle the mind, the most logical thing to do is downgrade the kernel. I know that I was able to successfully… analyze the matrices used for, oh, whatever it was… back at the beginning of June, which means I had working Bluetooth on June 1. Let’s see what kernel was latest then, download and install it, boot from it, and…

kernel: usb 8-4: USB disconnect, device number 3
kernel: usb 8-4: new full-speed USB device number 4 using ohci-pci

#$@&%*!

Ok, the hardware must be dying.  Stupid Atheros card.  No idea why it’s just the Bluetooth and not the WiFi as well, but we’re in Ireland and I’m on eBay, so I’ll just order another one.  Made by a different company.  A week later, a slightly used Ralink combo card shows up. I plug it in, fire her up, and…

kernel: usb 8-4: USB disconnect, device number 3
kernel: ohci-pci 0000:00:13.0: HC died; cleaning up
kernel: ohci-pci 0000:00:13.0: frame counter not updating; disabled

Double #$@&%*! Now the Bluetooth module is completely gone and the only way to get it back is to reboot. Grrrrr.

At this point I’ve got a hammer in my hand, my laptop in front of me, and the only thing keeping me from submitting a video for a new OnePlus One is my wife warning me that we’re not going to be buying me a new laptop any time this decade.

So I take a deep breath, calmly return the hammer to the toolbox (no, dear, I have no idea how that dent got on the toolbox), and decide to instead go down the road less traveled. I open up Fedora’s bugzilla and start preparing my bug report, taking special care to only use words that I’d be willing to say in front of my children. “…so the Bluetooth module keeps getting disconnected. It’s almost like the USB bus is cutting its power for some stupid…”

Wait a minute! Just before we traveled to Ireland, I remember experimenting with PowerTOP. And PowerTOP has this cool feature that allows you to automatically enable all power saving options on boot. And I might have enabled it. So I check, and, yes I have turned on autosuspend for my Bluetooth module. I turn it off, try to connect my… portable Bluetooth controller… and it works, first time. I do some… matrix analysis… with it and everything continues to work perfectly.

So I am an idiot. I close the page with the half-finished bug report and go to admit to my wife that I just wasted €20 on a WiFi card that I didn’t really need.  And, uh, if any Atheros or Ralink people read this, well, I’m sorry for any negative thoughts I may have had about your WiFi cards.

[1] Well, mostly true, anyway. Some of the details might be mildly exaggerated.