[LAU] /dev/rtc permissions on Debian

[R. Mattes]

On Sun, 08 Jan 2012 19:14:39 +0100, rosea.grammostola wrote
> On 01/08/2012 12:40 AM, James Stone wrote:
> > On 1/7/12, rosea.grammostola<rosea.grammostola at gmail.com>  wrote:
> >> Hi,
> >>
> >> cannot set tick on /dev/rtc permission denied

What a unhelpful error message! can't they at least include information
on the value that was supposed to be used?

> 
> same here, but the audio group has also the rights for /dev/rtc

We need the permissions of the actual device file (/dev/rtc0) , _not_
the link since the link permission only describes who is allowed to
follow the link.
   
> But still I get the message when launching Oostudio (openoctave / 
> oom).

You might have your settings for the maximum value set too low. What does
the following show:

 $ cat /sys/class/rtc/rtc0/max_user_freq

On older kernels that should be:

 $ cat /proc/sys/dev/rtc/max-user-freq

Also relevant:

 $ cat /proc/sys/dev/hpet/max-user-freq 

You can set these values like this:

 $ sudo echo 2048 > /sys/class/rtc/rtc0/max_user_freq
 $ sudo echo 2048 > /proc/sys/dev/hpet/max-user-freq

or set them in /etc/sysctl.conf

HTH Ralf Mattes