Re: [LAD] Drivers for RME (USB) MADI device (Madiface XT) - Linux-audio-dev

19 Aug 2014

On Mon, 11 Aug 2014 15:06:24 +0200 Adrian Knoth wrote:
...
  On 08/11/14 05:47, D. Sen wrote:
  I was advised by Paul Davis to inquire on this
list whether there has
 been or is likely to be any activity in developing ALSA drivers for the
 RME Madiface XT device. Its a USB device and as such makes it very
 amenable to a portable audio work.
 I have used PCIe based Madiface in the past using ALSA. However, I could
 not get the USB based Madiface XT to work. The device was recognized
 correctly (as per the SYSLOG) - however no drivers were loaded.
 Any help would be very much appreciated. 
 As I said a year ago, it should also be possible to sniff the USB
 connection, but this requires a device and a volunteer to do so. You'd
 then run Windows in a VM and capture the USB packets with wireshark or
 any other USB sniffer.
 Jonathan Woithe may have additional information, since he wrote the
 drivers for FF400 and FF800. 
The FF400 and FF800 are, obviously, both firewire devices.  Due to the bus
structure and the way it operates there will be nothing in common between
this and any of the RME USB or PCIe interfaces.  The drivers for the FF400
and FF800 are in FFADO, and while you may get some high level ideas from
things like our mixer interface, unfortunately our existing code is unlikely
to provide much in the way of direct assistance when looking at devices
using other interfaces.
Having gone down the protocol analysis route before (albeit not on the RME
devices) what Adrian has suggested is entirely feasible for the USB variant.
It will be time consuming, but sniffing the USB bus isn't difficult
technically speaking and - most importantly - doesn't require special
hardware now we have VMs.  Obviously the ideal situation is to obtain
documentation from the manufacturers, so contacting them as Adrian suggested
would be worth a shot.
Regards
  jonathan