linux/armv6 (Raspberry PI) notes

[pteichman]

Here are some notes on getting Sigourney up in Raspbian (currently based on Debian Wheezy). This isn't exactly a bug report, more like vaguely related observations--maybe there's a better place for it? So far none of this is actionable in Sigourney, though as you'll see there are probably bugs to come.

You'll need a newer go than is provided (Raspbian has 1.0.2; gorilla/websocket and sigourney/audio require 1.1). I used Dave Cheney's armv6 binaries of 1.3: http://dave.cheney.net/unofficial-arm-tarballs

Set GOPATH and PATH. I assume you know your way around a go dev environment.

$ aptitude install mercurial libportaudio2 libportmidi-dev
$ go get github.com/rakyll/portmidi

This will fail because -lporttime needs to be added to the linker line. Edit $GOPATH/src/github.com/rakyll/portmidi/portmidi.go and modify the cgo LDFLAGS line to read:

// #cgo LDFLAGS: -lportmidi -lporttime

Now the sigourney install should proceed as described in its README:

$ go get -u github.com/nf/sigourney

Force audio output to the headphone jack (rather than HDMI).

$ sudo amixer cset numid=3 1

Run the sigourney demo.

$ $GOPATH/bin/sigourney -demo=true

The output is very noisy (white noise underneath) especially at the shorter sustain end of the demo's cycle. This wasn't helped by upgrading the rpi firmware (sudo rpi-update).

There are a bunch of ALSA errors when sigourney starts, complaining about unknown surround channels. Those don't seem to affect the audio output.

Websockets aren't coming up properly for the web interface: loading http://<listen address>/ yields "Connecting to back end... Lost connection to back end!".

Whether USB MIDI can work out of the box is still TBD: I'm not seeing any notes in the console after adding logging.

The demo holds steady at ~45% CPU for now. I'll look into the above.

[nf]

Thanks very much for sharing. Hopefully this will help others.