EAFNOSUPPORT despite kernel build in

[Johannes Holtz]

Hello,

When I request a socket with AF_RTIPC I get an EAFNOSUPPORT in return.
int sock = socket(AF_RTIPC, SOCK_DGRAM, IPCPROTO_IDDP);

rtipc.h is included
#include <rtdm/rtipc.h>

I have build the support for RTIPC into the kernel (not a module) and
expected this to work more or less out of the box. Did I forget something
or must this feature be a module?
I have searched for a solution but haven't found anything.

Here information about the system:

virtual machine (VBox) with 1 CPU,  2.5GB RAM, 15GB disk

base kernel version is 3.18.20

xenomai  version is 2.6.5 (from the download page not from the git repo)

using the included ipipe patch
xenomai-2.6.5/ksrc/arch/x86/patches/ipipe-core-3.18.20-x86-7.patch

the kernel config has the feature enabled
root at xeno:~/kernelbuild# grep RTIPC /boot/config-3.18.20
CONFIG_XENO_DRIVERS_RTIPC=y
CONFIG_XENO_DRIVERS_RTIPC_XDDP=y
CONFIG_XENO_DRIVERS_RTIPC_IDDP=y
CONFIG_XENO_DRIVERS_RTIPC_BUFP=y