On Thu, Jul 12, 2012 at 09:24:34PM +0200, Atte André Jensen wrote: > I'm trying to use my novation launchpad with chuck. It seems to be > plug/play, at least I didn't do anything except plug and play :-) > > However it's acting a bit strange in one regard. The first time I > handle (read presses from the launchpad and sends something back to > turn lights on/off) it works as expected. > > However the next time I launch my chuck code (without turning off = > unplugging the launchpad) it doesn't send presses. However the arrow > up, down, left and right buttons (or at least the up-one, that's > what I got used to use) works and after pressing it the other > buttons start sending again. > > Every once in a while, it's the other way around, I have to press a > grid button before the arrow pads start sending. > > I checked my chuck code quite thoroughly, and played with various > things to remedy the problem, but still it might be something I send > that messes up the launchpad. > > Can anyone recognize this behavior? Or the opposite: testify that it > works without this quirk? Any ideas how to approach the problem, > narrow down the possibilities and hopefully eventually find a fix? That is because the LP sends MIDI using running status, and there is no way to reset it (i.e. force a status byte on the next message), except a power cycle. The top row uses controller events while the rest uses key up/down. After re-opening the device the driver code needs a status byte, and usually using the top row will provide one (assuming the last event in the previous session was a key one). Actually *most* events are unambiguous even without a status byte, but you'd need some ad-hoc code in the driver to exploit that. Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow) _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
