About ipc_key, ipc_gid and ipc_perm

About ipc_key, ipc_gid and ipc_perm

[Simon Tremblay]

Hi,

someone knows to what is related ipc_key, ipc_gid and ipc_perm settings
in /usr/share/alsa/alsa.conf file?

I ask that because even if I don't have an audio group created on my
embedded system, I can play a wave file with aplay.

But since I want to use -D plug:dmix option, I can't. It asks me to
create audio group.

But after that, I have a strange error I can't explain: audio open
error: Operation not permitted.

I think ipc_perm has something related to chmod 0660 file?

But what is ipc_key ? Does I have to set it somewhere since I installed
manually alsa on my system ?


Also, On SuSE, I see a + at the end of permission listing of each device
 file. What does it mean? Like this:

crw-rw----+ 1 dax audio 116, 7 2008-08-13 14:06 controlC0
crw-rw----+ 1 dax audio 116, 3 2008-08-13 14:06 midiC0D0
crw-rw----+ 1 dax audio 116, 6 2008-08-13 14:06 pcmC0D0c
crw-rw----+ 1 dax audio 116, 5 2008-08-13 14:06 pcmC0D0p
crw-rw----+ 1 dax audio 116, 4 2008-08-13 14:06 pcmC0D1p

I don't have that on my embedded system, is it something related only to
SuSE ?


Thanks,


Simon