Arch Linux

Might i add tis was also the case with 2.6.14

Hi Lou,

I'm a little stumped by this one. AFAICT, it *should* be working. Neri originally set up the rtprio stuff in PAM, but he's in inter-continental transit right now, so we can't ask him.

For the time being, I've been using this workaround with qjackctl/jackd. I've attached the PKGBUILD.

I was experiencing the same problem too but I made it work. I did the following:

1. In /etc/security/limits.conf, I moved the default rules for the bottom of the file, since the documentation of pam_limits says that the first rule that matches the current user will be used. So, the default (*) must be the last, for the particular cases to be trapped first.

2. I am using KDE, with KDM to login. As the /opt/kde/share/doc/kdm/README says, the default service name that KDM uses when the pam support is active is kde, but in the /etc/pam.d directory there is only a file named kde-np, that instructs kdm to use pam_limits for the session part of the authentication. So, I did, as root:

ln -s /etc/pam.d/kde-np /etc/pam.d/kde

And it worked. The problem is that kdm was not finding the configuration file for PAM and so it couldn't use the pam_limits to change limits for the logged user. The real solution to this is to change the package that owns kde-np (witch is kde-common). Either change the file kde-np to kde or recompile kdm (witch is in kdebase) to read the pam configuration from kde-np.

I deeply hope that this helps to solve this problem.

moved to tpowa due to it seems and kde bug.

problem is that the provided fix, will enable everyone to login without any password

Ahh, that's quite a problem, was there another fix which in current kde-common which bypasses this and still works? It's still not working for me and it's rather essential if you want to do audio work.

Hi. I'm im my job and can't test this right now. But what I meant in the solution was that the login procedure for KDE was not considering the /etc/security/limits. By what I remember, the /etc/pam.d/kde-np file instructs the same things as /etc/pam.d/login. It seems that both load pam_unix2 (I think...) to verify the password. And when I mistype my password, it refuses to login, as I wuold expect.

As I said, I must confirm this first. But I think that it doesn't do this. I am using arch for audio with no problems. Jack is runing in realtime and a lot of others applications run fine, including Ardour, Muse, Hexter, Om-synth and ZynAddSubFx. No problems at all...

Well, after the tests, I saw that the login in kdm was a big hole... Oh God. And if you look into /etc/pam.d/kde-np you see that it is very different from /etc/pam.d/login, which is the responsible for the pam configuration of the terminal login. So (one more hack doesn't hurt), I softlinked /etc/pam.d/kde to /etc/pam.d/login and it worked. Of course this is not a final solution, but works for me. I'll keep with this until /etc/pam.d/kde-np is fixed for someone with more experience in pam than me.

And for the realtime part of the problem, my /etc/security/limits.conf is like this:

@audio - rtprio 99
@audio - nice -20
@audio - memlock 40000
* - rtprio 0
* - nice 0

And I can use realtime for audio without any problems. Take a note on the rtprio and nice values. I took this from the Linux Audio User list.

tpowa: You can simply add this line to the end of /etc/pam.d/kde:
session required pam_limits.so

This really should be added to kde-common package.

added to kde 3.5.3

No longer fixed. GDM uses pam_limits.so as it should, and jack won't run properly; it's possible that a necessary compile option is missing from the kernel, but I'm not sure.