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elisa and lirc hacking

Filed under: Dave/Dina,Fluendo,Hacking — Thomas @ 12:21 am

2007-2-20
12:21 am

So, after waiting for months and months on a DirectFB backend for Elisa so I could use my home Dave/Dina machine with it (It has a venerable Matrox G550 which is the best type of card to use with DirectFB), I caved in last week and joined the dark side by buying an NVidia GeForce FX 5200 card and using the binary-only drivers. It took some tweaking and digging, but I managed to get the card a) output with TV/out, b) look good enough to be comparable to the Matrox video output, and c) avoid any tearing effects by enabling all the VSYNC options the tools provided me.

Loic recommended a higher-numbered card, but all cards in the series he recommended have fans, except for one particular model that you have to mail-order from Asia. I want as few fans as possible in my media box.

I hate saying this, but the NVidia configuration tools actually work pretty damn well once you get the hang of it. Most changes are done on the fly (without restarting X), which is a welcome change from the usual hackery. And when I read the README for these drivers and look at the huge amounts of tweaking you can do with these cards (genlocking 4 cards together ? Are they serious ? Is there any open driver out there that can come close to offering something like this ?) I have some amount of respect for the NVidia Linux engineers. I hope the nouveau guys are going to hang in there and deliver on their mission goals, because they have a lot of work cut out for them.

I’m not advocating closed drivers at all, but for the time being I have decided to be practical about this and start hacking on Elisa and actually use it at home, and the NVidia card I got achieves that for now. I could get an LCD TV to avoid having to mess with TV/out, but I feel that there is still a large group of users that want to use something like Elisa with their existing analog TV.

Ironically enough Julien started hacking on a DirectFB renderer for Elisa a few days after I got the NVidia card :)

After that, I upgraded my base distro from FC4 i386 to FC6 x86_64. Again I reacquainted myself with the painful process of getting LIRC to work. Every time I put some serious effort into getting the media box up to date, I am forced to deal with LIRC, and every time I wonder why this has to be so painful. Here are some of the things about lirc that bother me to no end since I started using it five years ago:

  • Why is this stuff not in the kernel ?
  • Why is it so incredibly hard to set up ?
  • Why do all the configuration files for remotes use different namings for the same keys ? This should be a matter of policy dictated by the project. Why does one config file use “FastForward”, another “FWD”, and yet another “>>|” to mean the same thing, forcing someone to change the configuration of LIRC to work with their applications when they change the remote they use ?
  • Why is there only a terrible command-line application to “train” for your remote ? Elisa should be able to make a simple graphical remote trainer application that helps you set this up from scratch in a user-friendly way.
  • The worst part for me is the fact that this iMon device being used on my Silverstone media box comes with this dinky remote that has some sort of jogwheel that is able to simulate a mouse. Except the driver in lirc ignores that completely, so where every other remote has at the very least UP/DOWN/LEFT/RIGHT as part of the things it can generate, this one can’t. And then you get this forum where some guy put an original patch to make the jog wheel be able to generate up/down/left/right, and then you have a bunch of people modifying this patch, customizing, ripping out bits that fail to compile with later kernels, … But this stuff never gets upstream
  • A year ago I took one of those patches and fixed the kernel module to be a lot more consistent about the events it generates. The kernel driver actually receives fine-grained x/y coordinates from the jog wheel, and then synthesizes the four directions from this. It was doing so with a pretty bad algorithm, making it really hard to consistently go in a given direction. I had a patch for that. Except it needed updating for the newer 2.6.19 kernel, and apparently some things have changed in the input device layer. Sometimes I don’t understand why it’s ok for something as basic as the kernel to change their internal API all the time, while something like GStreamer, and pretty much everything in the GNOME stack, is forced to be held up to such high API standards
  • .

    Anyway, after all the hardware hacking and distro updating, I have an elisa running at home, with the remote working, and able to show me Veronica Mars, Heroes and Battlestar Galactica.

    Next tasks: push Fedora Extras packages, look at why subtitle rendering is so slow that a 2GHz Athlon64 cannot play the video fast enough from within Elisa, and taking a look at the music parts.

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