Linus pointed this out a long time ago
From the kernel log:
At commit 07d106d0, Linus pointed out that ENOIOCTLCMD should be translated as ENOTTY to user mode
Improve reliability of speed tests for 3.14 kernels
Fix reliability of speed tests
Set the number of allowed dvbloopback devices to the maximum of 32
also remove more old kernel stuff in dvbloopback.h
Loose stupid info
Prepare for linux-3.17