[ecasound] SCHED_FIFO permissions

Hi, I'm having a rather vexing problem:

I'm trying to run ecasound on a Odroid XU4 running Ubuntu 15.04 with a
Behringer UCA202 using the following command:

 ecasound -b:256 -f:s16_le,1,44100 -i alsahw,1,0 -o alsahw,1,0

and I'm getting the following message:

**************************************************************************
* ecasound v2.9.1 (C) 1997-2014 Kai Vehmanen and others
**************************************************************************
(eca-chainsetup-parser) Setting buffersize to (samples) 256.
(eca-chainsetup) Chainsetup "untitled-chainsetup"
*(eca-chainsetup) NOTE: Real-time configuration, but insufficient
privileges*
*... to utilize real-time scheduling (SCHED_FIFO). With small buffersizes,*
*... this may cause audible glitches during processing.*
(eca-chainsetup) "rt" buffering mode selected.
(eca-chainsetup) Opened input "alsahw", mode "read". Format: s16_le,
... channels 1, srate 44100, interleaved.
(eca-chainsetup) Opened output "alsahw", mode "write". Format: s16_le,
... channels 1, srate 44100, interleaved.
- [ Connected chainsetup: "untitled-chainsetup" ] ------------------------
- [ Controller/Starting batch processing ] -------------------------------
- [ Engine - Driver start ] ----------------------------------------------
^C- [ Controller/Batch processing finished (0) ] ---------------------------

I'm getting an unacceptable amount of latency (around 300 ms). With a
Beaglebone Black running Debian I could get down to about 10 ms latency
with the buffer set to 64.

I'm running as root and I think I have sufficient privileges, output from
capsh and ulimit -a are show below. I tried increasing the debug level and
it's not giving me any more information on why ecasound thinks it can't set
SCHED_FIFO. I assume it's some kind of system setting but it would help to
know what system call is failing so I know where to start looking. Any help
would be most appreciated.

John

root@email-addr-hidden:~# capsh --print
Current: =
cap_chown,cap_dac_override,cap_dac_read_search,cap_fowner,cap_fsetid,cap_kill,cap_setgid,cap_setuid,cap_setpcap,cap_linux_immutable,cap_net_bind_service,cap_net_broadcast,cap_net_admin,cap_net_raw,cap_ipc_lock,cap_ipc_owner,cap_sys_module,cap_sys_rawio,cap_sys_chroot,cap_sys_ptrace,cap_sys_pacct,cap_sys_admin,cap_sys_boot,cap_sys_nice,cap_sys_resource,cap_sys_time,cap_sys_tty_config,cap_mknod,cap_lease,cap_audit_write,cap_audit_control,cap_setfcap,cap_mac_override,cap_mac_admin,cap_syslog,cap_wake_alarm,cap_block_suspend+ep
Bounding set
=cap_chown,cap_dac_override,cap_dac_read_search,cap_fowner,cap_fsetid,cap_kill,cap_setgid,cap_setuid,cap_setpcap,cap_linux_immutable,cap_net_bind_service,cap_net_broadcast,cap_net_admin,cap_net_raw,cap_ipc_lock,cap_ipc_owner,cap_sys_module,cap_sys_rawio,cap_sys_chroot,cap_sys_ptrace,cap_sys_pacct,cap_sys_admin,cap_sys_boot,cap_sys_nice,cap_sys_resource,cap_sys_time,cap_sys_tty_config,cap_mknod,cap_lease,cap_audit_write,cap_audit_control,cap_setfcap,cap_mac_override,cap_mac_admin,cap_syslog,cap_wake_alarm,cap_block_suspend
Securebits: 00/0x0/1'b0
 secure-noroot: no (unlocked)
 secure-no-suid-fixup: no (unlocked)
 secure-keep-caps: no (unlocked)
uid=0(root)
gid=0(root)
groups=0(root)
root@email-addr-hidden:~# ulimit -a
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 99
file size (blocks, -f) unlimited
pending signals (-i) 11894
max locked memory (kbytes, -l) 1000
max memory size (kbytes, -m) unlimited
open files (-n) 1024
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 99
stack size (kbytes, -s) 8192
cpu time (seconds, -t) unlimited
max user processes (-u) 11894
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited

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Received on Tue Jul 28 08:15:01 2015