Re: [Gumstix-users] open("/dev/mem"): Operation not permitted

[Dave H. <dhy...@gm...>]

Hi Matthew,

> I recently introduced all the previous work from this thread :
> http://old.nabble.com/RS485-on-the-gumstix-basix-and-verdex-via-direct-IO-td25607594.html
>
> into my standard application and it worked great until the test system ran
> the application as a non-root user.
>
> my error is :
>         open("/dev/mem"): Operation not permitted
>
> I believe this means that my user is not allowed access to the /dev/mem
> "file".
> I presume that there's a sensible way around it, but I don't know what it
> is.
>
> I did try, against my better judgement, to make /dev/mem world readable and
> writeable to see if that made a difference. which it didn't!
>
> I even did a
> % chown factory.factory /dev/mem
> but that didn't help either.

Only root is allowed to access /dev/mem.

So you either have to run your app as root, or use a real device
driver rather than trying to use /dev/mem.

-- 
Dave Hylands
Shuswap, BC, Canada
http://www.DaveHylands.com/