Re: [Discuss-gnuradio] shmat issue

[Philip Balister]

On 10/19/2010 10:51 PM, Eric Blossom wrote:
> On Tue, Oct 19, 2010 at 08:34:40PM -0400, Philip Balister wrote:
> > I'm seeing this issue on my omap3 install with the dialtone flowgraph:
> >
> > # python /usr/share/gnuradio/examples/audio/dial_tone.py
> >
> >
> > gr_vmcircbuf_createfilemapping: createfilemapping is not available
> >
> > gr_vmcircbuf_sysv_shm: shmat (3): Invalid argument
> >
> > l# python /usr/share/gnuradio/examples/audio/dial_tone.py
>
> > From $ man shmat
>
>    EINVAL Invalid shmid value, unaligned (i.e., not page-aligned and SHM_RND  
> was  not  speci-
>           fied) or invalid shmaddr value, or can’t attach segment at shmaddr, 
> or SHM_REMAP was
>           specified and shmaddr was NULL.

I hate system calls that have one error code for several errors.

> > In both cases I can hear the dial tone fine. I'm curious why I get
> > the shmat error the first time only.
>
> You should see it only once ever, if the program can write to
> ~/.gnuradio/prefs.  Generally this gets written during "make check".
>
> Does "make check" work?

Insert whining about make check for the cross compiled case :)

> Why are you running as root?

I am lazy :)

> > It looks like gnuradio falls
> > back to another method of creating the shared segment.
>
> Yes it does.
>
> > I'd like to resolve the shmat issue though,
>
> Set a breakpoint with gdb, or add printfs.

OK, it looks like x86 sets SHMLBA to PAGE_SIZE and arm uses 4 * 
PAGE_SIZE. Need to puzzle through this a little more. This is the 
failing check in the kernel.

Philip


> > because I am also trying to run the kalibrate program and have the
> > same shmat issue there, but it does not have a fall back method.
>
> Eric