[PlanetCCRMA] rt-kernel and firewire

barb barb at col-me.info
Wed May 2 13:49:19 PDT 2012

i am new on this mailinglist and only here to investigate one thing i am 
working on currently. to connect the firewire saffire focusrite to my 
fc16 machine i am using the 3.0.17-1.rt33 kernel.

the problem is, that i can only start up jack with firewire drivers (i 
use the new stack) when i am root. of course all the programms 
connecting to jack afterwards have to be started as root as well, which 
is not what i am aiming at.

if i start them as user, i get a 'permisison denied' on the libffado. i 
checked all the permissions and am finally part of any group that exists 
on the system without success. the /dev/fw0 is set on a group, which i 
am part of (rw permissions for u+g).
i found a manual proposing to make a custom kernel and to disable 
GROUP_SCHED in it, as otherwise realtime scheduling as normal user would 
be not possible.
--> http://en.gentoo-wiki.com/wiki/JACK#Kernel_Configuration

so i did. as i am not really experienced in compiling my own kernels i 
awfully failed with conflicts with installed kernel-headers on the 
rt-custom-kernel and also saying, that i have a newer version installed 
(but i did change the kernel.spec and the build-id).

so my questions are if i really need a newly compiled rt kernel with 
GROUP_SCHED disabled to get firewire running under a user or if i am 
doing something else wrong. and in case i need to compile the kernel, 
where can i get help for very probably wrongdoing from my side from 
experienced kernel compilers?

i'd be happy for advise on this issue
thank you very much


callme at col-me.info
Bratislava / Slovakia

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