Re: impossible to access /dev/mem on RPi B+ [Was: Sound issues on RPi B+, Jun's latest image]

[christos%astron.com@localhost (Christos Zoulas)]

In article <CAFTWPd+uV0ZDB+0q5mueGtO+i5tEjyu3v_y_vrQV-iXTiS4ydQ%mail.gmail.com@localhost>,
Jean-Baka Domelevo Entfellner  <domelevo%gmail.com@localhost> wrote:
>-=-=-=-=-=-
>
>Thanks Jun,
>
>I want to clarify/correct two things:
>
>(1) The most important issue is the impossible access to /dev/mem, even
>being root. This character device is registered in /dev/ with major=0 and
>minor=0. user is root, group is kmem and rights are rw-r-----. Apparently
>this prevents full use of the GPIO as we have to map memory regions, like
>in the code snippet given at the end of this email (taken from
>http://elinux.org/RPi_Low-level_peripherals#C).

This probably has to do with sysctl kern.securelevel?

christos