Making the Hercules DJ Control MP3 work with Mixxx

(Note: files updated for Ubuntu 8.04)
(Another note: this is all unnecessary now, as Hercules has released Linux drivers for their devices. Just install, and away it goes.)

A little while back, I got a Hercules DJ Control MP3, which is an entry-level DJ console that connects to the computer with USB. Unlike most of these kinds of things, this isn’t a MIDI device, so making it work requires a bit of hacking.

Mixxx supports the Herc DJ Control Mk1 and Mk2 just fine, by talking to them directly over USB, unfortunately the Control MP3 requires some magic for this to work that noone has figured out yet. However, the kernel can talk to it using the HID system, which usually is used for keyboards, mice, and other random controllers. The problem with this is that the LEDs don’t work. For some reason, the Linux kernel (as of 2.6) ignores any LEDs that the device says it has if it doesn’t know what they are. With a bit of kernel hacking, this behaviour can be changed, and then Mixxx will use it just fine. If you don’t do this, the controls work, but the LEDs don’t. And we all want blinky LEDs, don’t we? 🙂 (Also, I used some of the spare LEDs on the controller and made them into a VU meter, which works surprisingly well.)

So to start with: making the kernel work right. I’ve made a patch against the Ubuntu 2.6.22 2.6.24 kernel, here. Or, if you are using Ubuntu 32-bit with this kernel, you can just use these two modules: hid.ko and usbhid.ko. (Files for Ubuntu 7.10 are also available). With the Herc unplugged, do:

sudo rmmod usbhid; sudo rmmod hid; sudo insmod hid.ko; sudo insmod usbhid.ko

(it pays to do them all on one line, as USB keyboards and mice may stop working while the module is unloaded). If these load properly, then you’re half way there.

The next step is to make Mixxx work with this. By default, it only supports the Mk1 and Mk2, as it uses the direct USB way of talking to them. To make it use HID, you need to recompile it, using the current SVN version. How to do this is documented on the Mixxx website, but the compile command needs an extra option, thus:

scons djconsole_legacy=1

The binary that this spits out should handle the LEDs just fine.

This is all very hacky, but hopefully it won’t be in the future. I’m going to see if I can get that patch put in the kernel proper, which will solve the most annoying part of the problem. It would also be good to get Mixxx supporting both legacy mode and the newer one at the same time.

However, we’ve heard from Hercules, and they say that some time in the first part of this year, they’re going to try to get some Linux drivers out. Hopefully they’re open source, and turn the Herc devices into MIDI devices, which would make life a whole lot easier for support.