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2009-12-15

When your hobby becomes a job: reflections on the em28xx driver situation

Filed under: Programming,Software — rg3 @ 21:59

More than one year ago I bought a TV USB stick to be able to watch analog and digital TV in my computer running Linux. It was not an easy task. As you may know, usually it’s not hard to find hardware that is supported by Linux. Sometimes, however, while there are multiple devices supported that would serve your purposes, the trouble will be locating a place or site that will have one of those models available for you to buy. This was my case. I printed a list of supported digital and/or analog TV tuner USB devices and went to most computer stores and malls in my area trying to locate at least one of them and compare prices, and I went back home with hands empty.

I had to change the strategy and get the list of devices I could buy, and then search for them on the Internet, trying to know if any of them were supported by an out-of-tree driver or something similar. After a couple of returns, thanks to some manufacturers changing devices internally while keeping the product name unchanged, I finally arrived home with a working, hybrid, TV USB stick, the Pinnacle PCVT Hybrid Pro Stick, sold in some countries as model 330e. It costed just over 100 euros.

My main target being digital TV, I quickly got it working with an out-of-tree driver by Markus Rechberger. This out-of-tree driver was part of a project that tried to create the possibility of having user-space tuners for TV cards. While I am nobody to judge if that’s a good or bad idea, it was different enough to not make it into the main kernel tree. The author, then, appeared to change the approach and created a different out-of-tree driver called “em28xx-new”, based on the in-kernel “em28xx” driver that he had already contributed. This driver used a more traditional approach, and worked like a charm too. Unfortunately, it never made it into the vanilla kernel either, for whatever reasons.

I contacted Markus Rechberger a couple of times, if I recall correctly. I thanked him for his efforts and time put into creating the driver and asked a couple of questions once, and also sent him a patch for the build scripts some time later. I don’t recall if the patch was applied or not. He was always very nice and polite.

However, one day I had just compiled a new kernel and was about to build the driver for it. Before doing that, I always downloaded the latest copy of the driver source code from its Mercurial repository. This time, when I ran Mercurial it exited with a confusing error message, saying the remote tree was not the same repository I had in my hard drive. I supposed the author would have created a new repository for the driver, so I cloned it to a new directory. It turned out there was only a README file in the repository. I opened it and… uh oh. A note saying the old driver had been pulled from the Internet and giving a URL that led to the web site of a TV card manufacturer offering products that were supposedly supported by Linux. The equivalent USB stick costed just about 100 euros, like the one I had. But, of course, it was too late for me to return the one I had bought. I had been using the device for months.

I searched on the Internet again trying to find the reason that led to the driver being pulled from the web site, and everything I got was the site of an Arch Linux user that uploaded the latest version he got from the repository and even offers some patches to make the code work with more recent kernels. However, as of the time I’m writing this, the latest patch is for kernel 2.6.30 and the driver does not compile for the recently released kernel 2.6.32. So the status of this device is that it works, but only if you have a specific kernel version. At the top of that page, you can see a huge banner that reads like this:

DISCLAIMER: Don’t bother me or the original author, Markus Rechberger, with any questions about problems with this driver, because Markus Rechberger deleted it because of these questions and because I just host these files.

I thought the driver may have been pulled from the Internet for some kind of legal reasons, but the disclaimer suggests a different reason. I don’t know if I buy the reason. I’m not sure it’s entirely credible but there’s no point in not believing those words are true. Markus Rechberger, for all we know, got burned out maintaining the driver and decided not to maintain it any longer.

A story published months ago at lwn.net explains this case with more details and further information. The situation for people owning this device and wanting to use it under a recent kernel is that you are supposed to be using the in-kernel em28xx driver. However, as the linuxtv.org page for the device says, the difficulty in supporting digital TV for it has its source in the Micronas DRX3975D DVB-T chipset it features. This chipset already has an in-kernel driver, which can be located at Device Drivers > Multimedia support > DVB/ATSC adapters > Customize the frontend modules to build > Customize DVB Frontends > Micronas DRX3975D/DRX3977D based. The location may change in the future (2.6.32 as I’m writing this).

Unfortunately, the driver cannot be used by now. As its help text mentions, this driver needs external firmware which currently cannot be obtained. Marked as “TODO” in the help text, you are told to run “<kerneldir>/Documentation/dvb/get_dvb_firmware drx397xD”. But, if you try, you’ll get an error saying that drx397xD is not a know component.

It’s an appropriate moment to thank and encourage the developers that are working on this, being the last missing piece. Devin Heitmueller has done a good job trying to keep people up-to-date with information on the progress and the difficulties encountered. The last comment on that blog post is from December 6 and says:

Unfortunately, at this point the answer is “not right now”. I’m waiting for the DVB generator to arrive, at which point I should be able to complete the work.

Again, thanks for working on this, keep up the good work and we’re eager to make our 330e USB cards work again with recent kernels, Devin!

While reflecting on the driver situation and putting together the different pieces of this soap opera, it all reminded me of the situation we professional programmers face from time to time while maintaining open source software. Many of us really love programming and we have tried to make it our job, successfully. There’s a difference, however, when you change from student to professional programmer.

When you are a student, you have a lot of time in your hands. It’s a wonderful experience going to college and learning new things everyday, buy books, read about different languages and technology, and the amount of spare time to learn and have fun programming is incredible. Later, however, you become professional and you start working for a company in a full time job. You leave home before dawn everyday and, at least in winter and in my case, you arrive home after sunset. It’s incredibly depressing if you think about it. You spend the day coding, fixing issues in programs, debugging, testing, etc. This kind of life doesn’t make it impossible to enjoy programming again, but if you arrive home and find that you have a popular open source program in your hands with users reporting bugs and requesting new features you may feel as if you were still at the office.

My advice here is obvious. Don’t stop coding in your spare time, but do it for fun. If you don’t feel like adding a new feature someone requested, don’t add it. It’s very important to say “no” often so your program will still be your program, the product you wanted. If a user or a group of users are still in the fortunate situation in which they are students and have a lot of spare time, they can always fork your code. That is the beauty of free and open source software.

I couldn’t care less if some people would like to use all this text above to attack FOSS and say bad things about it: non-working drivers, unresponsive maintainers, lack of documentation, user unfriendliness. Mental health of the people writing the code is more important. Don’t burn out. Produce something and let others make better things out of it if you don’t have the time. Start new projects all the time. Handle maintenance of old projects to new people. Have fun. Enjoy. Code. Help others. Submit patches with bug reports if possible. Appreciate the effort of others and thank them for the work they provide you. Try to be kind and explain your users the reasons behind your “noes”.

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