Atomic Ant build notes

Let me blow the dust off of this blog. Koff koff.

OK, a couple of weekends ago, since I was going to have some free time, I ordered a bunch of parts from NewEgg to build a new MythTV front end computer. The computer I was using as a front end was probably three years old, energy-inefficient, and couldn't play HD material without using XvMC as an assist. Unfortunately, a few months ago, for some unknown reason, anything on CBS in HD no longer played via XvMC... CBS always had the highest bitrate HD broadcasts, and apparently something changed about the signal and made it just a bit too much for XvMC. So I could watch 30 Rock on the front end but not The Big Bang Theory. This was clearly justification for getting a new computer.

These are the notes for building said computer and as such may be an exceedingly boring post to all of my 3 readers. Feel free to check out the 30 Rock quote instead.

I used as the model for this front end the "Atomic Ant" that Cecil Watson created over at the KnoppMyth forum (minus the tuner). It's very small, very quiet, capable of HD when using something NVIDIA is calling VDPAU (it allows for hardware-accelerated playback of both MPEG2 and x264 files, meaning that XvMC is ultimately doomed), and best of all when you price out all the components at NewEgg, only ran about $350. So I bought all the parts and got them in on Friday just in time for a fun weekend of squinting at jumper cables and cutting my knuckles on sharp edges.

The InWin case opened up fairly readily, but since it's such a small case there wasn't a lot of room to work. I probably should have removed the power supply in order to get the motherboard in place, but a little bit of forcing worked OK and luckily didn't snap the board in two. I snapped in the RAM, installed the hard drive, installed the passively-cooled NVIDIA video card (noting that I would have to make sure cables didn't touch the heat sink), wired up everything. All was going well... until I went to install the slimline DVD drive.

Slimline DVD drives say they have an IDE interface, which I guess they do, but they have a completely different connector than our friend the ribbon cable. Didn't know that. That was problem #1. Problem #2... slimline DVD drives want to be mounted in notebooks and use teeny-tiny screws to do so. Said teeny-tiny screws were not included with the slimline drive or the InWin case. So I couldn't use the DVD drive to install anything. (I've ordered an adapter to let the drive work with standard IDE ribbon cables, but it hasn't shown up yet, and I still can't find the screws I could use to mount it to the drive bay.)

Undaunted, I closed up the case, confirmed it could power up, and decided to try installing an OS by building a bootable USB memory stick. I found a utility called unetbootin, which works under Windows and Ubuntu. I was able to build a bootable Parted Magic drive, which allowed me to format the hard drive, but any attempts at building a bootable Ubuntu stick wouldn't work... the graphical installer would freeze. (I also then discovered that Ubuntu 8.10 actually includes the ability to build a bootable USB, but that didn't work any better.)

I forget exactly what error messages I typed in to find out why it wasn't working, but it turned out that it was some kind of conflict between the video card and the motherboard. By removing the NVIDIA video card and just running off of the onboard Intel video, I was able to get Ubuntu 8.10 running on the system. I then used Synaptic to install MythTV components (effectively getting Mythbuntu running on the system), and connected to my MythTV back end.

And what a surprise! On-board video let me play back 720p HD recordings no problem! Even 1080i recordings played back pretty well, although it did glitch from time to time. Power consumption was a mere 35-40 watts, it was darn quiet, all was well again...

But of course it wasn't! Hah!

If I tried to play back 1080i recordings at 1.2x speed (a great feature of MythTV), it would stutter during playback--it just couldn't handle it. So yesterday I decided to try to get the NVIDIA card back in the computer and get VDPAU working. I'd found this website by Jean-Yves Avenard that made it seem fairly easy to use his custom MythTV build, a few libraries, and the 180.xxx NVIDIA drivers to get it going under Ubuntu. Another plus is that it didn't require an upgrade of the MythTV database, which would be required if I'd run KnoppMyth R6, for instance.

First snag. Putting the card in the Atomic Ant and rebooting threw a ton of segmentation faults during startup. Very annoying, but searching for the motherboard part number turned up this thread on the Ubuntu forums that described the exact problem and the solution (blacklisting some AGP stuff... this was what was screwing up my initial installations, probably).

Second snag: I'd set the Ant's IP address to a static one, but hadn't added in any DNS info into /etc/resolv.conf, so couldn't find anything beyond my local address. Added my router as the primary DNS, rebooted, fixed.

Third snag: adding the URLs for the Avenard repository and running an apt-get update/upgrade wasn't sufficient to install the upgraded MythTV and NVIDIA drivers. After multiple attempts, I read on some web page that you need to remove all existing NVIDIA drivers before trying to install the 180.x drivers from his repository. After a few removals/reinstalls and checking the Hardware Drivers app, I finally got 180.x drivers running. Not sure why it took multiple attempts to do so. Things might have gone more smoothly had I removed the drivers before I tried installing.

Fourth snag: I got MythTV running, changed over the playback profile to use VDPAU for all video resolutions, and kerpow--trying to play anything resulted in an instant crash back to the Mythbuntu desktop. Needless to say, big snag here. Luckily I knew the drill: run mythfrontend from a terminal and add the option to log all activity to a text file. I checked the text file after the crash and it was complaining about not finding GLX running. It should be running--I instaled the NVIDIA drivers!

Nope, it wasn't running... nosing around in some forum posts with people having similar problems suggested checking the X.org logs. I found some command line command that grep'd the log for lines dealing with "nv". At the top of the log it was clear that the "nv" drivers were still in use and not "nvidia". So, the other step that was only offhandedly mentioned was that you have to manually edit /etc/X11/xorg.conf to load both GLX and to use the "nvidia" restricted driver. (Wish I could document this better but it's lunchtime and I'm hurrying and it's already too long and boring, eh?)

Anyhow, did this, rebooted, checked X.org logs, "nvidia" was in use (yahoo!), started up MythTV on the Atomic Ant, and -- YEAH BABY! Success.

At which point I thought to myself "this really would have been easier with a Mac."