[linux-audio-user] can't start jackd from normal user

[Antonio]

Hi Burkhard, Mark, Peder,

On Thu, 2005-09-29 at 09:19 +0200, Peder Hedlund wrote:
> 
> On Wed, 28 Sep 2005, Mark Knecht wrote:
 [cut]
I would suggest looking at how shm is mounted in your
> > distro and whether users are given access. On my Gentoo machine I have
> > this in fstab:
> >
> > shm                     /dev/shm        tmpfs
> > nodev,nosuid,noexec    0 0
> 
>  Make sure you have support for shm and tmpfs in the kernel.
>  (I think SHM is default but you have select
>  "Virtual memory filesystem support" under Filesystems/Pseudo fs)
> 
>  If you have that you shouldn't have to have any entry in fstab;
>  the kernel automounts /dev/shm with 1777 permissions.
>  I've read that having fstab mount /dev/shm after the kernel has mounted
>  it might cause xruns.
> 
>  The fstab entry, I think, is only for 2.4 kernels.

Sorry for not noting it was a permission issue with shm. I had compiled
"Virtual memory filesystem support" in the kernel. I have this situation
for /dev/shm:
  
  drwxr-xr-x  3 root root 60 2005-09-29 11:05 shm

Now, manually changing the permissions to /dev/shm with chmod works (in
the sense that I can start jack from normal user). Manually mounting shm
in this way:

  # mount -t tmpfs shm /dev/shm

works too, giving

  drwxrwxrwt  2 root root 40 2005-09-29 11:25 shm

unmounting shm I return to have the bad permission. If I put the stanza
in the fstab I get (well, obviously) the right permission on boot.

How can I obtain that shm is mounted on boot with the right permission
without the fstab entry? It really matters that fstab entry?

Thanks for the help.

Best Regards,

  ~ Antonio