[mythtv-users] SUID not working

[Steve Bower]

>>>>> "Doug" == Doug Larrick <doug at ties.org> writes:

Doug> The rlimit/PAM approach is the sanctioned way for a normal-user
Doug> application to get access to realtime scheduling.  It was the
Doug> audio-processing folks who lobbied for this support in the kernel;
Doug> we have them to thank.  FYI, The current PAM in Debian unstable
Doug> (what I run) already has support for this as of 0.76-8.

I've discovered that the FC4 pam-0.79-9.6 package now includes support
for this out-of-the-box, so there's no need to compile your own stuff to
get it working on FC4.

I did a "yum update pam" (which updated 4 packages), and added this line
to /etc/security/limits.conf:

  mythtv          -       rtprio          100

mythtv is the username I use for running my frontend process on login.

I noticed that under /etc/pam.d there were both "system-auth" and
"system-auth.rpmnew" files.  The ".rpmnew" one looked more correct, so I
moved it into place.  I don't know if this made a difference, so you may
not need to do so.

Anyways, then I logged out and back in my mythtv user session, and now
when I play recordings I get this in my mythfrontend log file:

  2005-11-05 10:30:05.875 Using realtime priority.

I haven't done extensive testing on it yet, but my initial impression is
that my 1080i playback looks at least a little bit better.

BTW, I got this working on two updates-released kernel versions:

  2.6.12-1.1398_FC4
  2.6.13-1.1526_FC4

The current one is 2.6.13-1.1532_FC4, so I imagine that'll work too.  I
think I read that support for this is part of the mainline 2.6.12
kernel.

Enjoy!

  Steve.
-- 
Steve Bower - IT/EHS Unix Administrator - sbower at cisco.com
The ideas presented herein aren't necessarily the ideas presented herein.