[mythtv-users] femon only works with mythbackend stopped?

Tom Dexter digitalaudiorock at gmail.com
Sun Nov 25 18:17:56 UTC 2007


On Nov 24, 2007 2:25 PM, Tom Dexter <digitalaudiorock at gmail.com> wrote:
>
> On Nov 24, 2007 11:42 AM, Paul Bender <pebender at san.rr.com> wrote:
> >
> > Tom Dexter wrote:
> > > I'm running Gentoo with media-tv/linuxtv-dvb-apps-1.1.1.20070114,
> > > media-tv/mythtv-0.20.2_p14324 and kernel 2.6.22-gentoo-r9.  I have
> > > three HD-5500 cards used only for ATSC OTA broadcasts.
> > >
> > > Everything I keep reading indicates that I should be able to monitor
> > > signal strength with femon while the backend is running, which would
> > > be awesome...I've been looking for a way to do that.  However it only
> > > works with the backend stopped.  If I try to use it while the backend
> > > is running the only output I get is:
> > >
> > > opening frontend failed: No such file or directory
> > >
> > > ...on all three of my adapters, even though the device files are there.
> > >
> > > Is this supposed to work?  If so, any ideas why it wouldn't?  Thanks.
> >
> > I have idea what femon is, so take my advice with a grain of salt.
> >
> > Using mythtv-setup, mythbackend can be configured to hold onto the tuner
> > cards either all the time or only when in use. You might try changing
> > that setting for your tuner cards and see if it helps.
> > _______________________________________________
> > mythtv-users mailing list
> > mythtv-users at mythtv.org
> > http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
> >
>
> I found something...it appears to be a bug in the cx88-dvb kernel
> driver.  It is in fact supposed to allow an arbitrary number of read
> accesses at once:
>
> http://www.mail-archive.com/linux-dvb@linuxtv.org/msg25730.html
>
> I'm checking right now to determine when/if that fix was incorporated
> into the kernel.
>
> Tom
>

That kernel patch worked perfectly, although I had to add 70 to all
the line numbers in the patch for it to apply to my kernel.  Now I can
even open a terminal on the frontend and ssh to the backend while
watching live TV and monitor the signal strength etc while adjusting
my antenna rotor....very cool.

I don't as yet see any sign of that patch or anything like it in any
kernels available in Gentoo portage, even in 2.6.23.

Tom


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