[mythtv-users] command "irsend" producing eratic results

Michael T. Dean mtdean at thirdcontact.com
Thu May 24 18:36:38 UTC 2007


On 05/24/2007 02:00 PM, Gary wrote:
> For the last hour I have been issueing "irsend" commands from a console.
> Some worked; some failed to work properly.
>
> The commands I used were:
> irsend send_once dish 1 2 0
> and
> irsend send_once dish 1 2 0 select
>
> Sometimes the commands did what they should have done (ie change the sat
> receiver to channel 120). 
>
> Sometimes the second digit was dropped; sometimes the third digit was
> dropped and once the first digit was dropped.
> I had mythtv running (full screen) with a console running as the active
> task so that the commands could be issued, and the results viewed.
>
> What are we seeing here, a bug in irsend or a failure in the satellite
> receiver???

My guess is that it's a timing/configuration issue, or some DISH network 
firmware update made the IR receiver a lot more picky about its signals.

Please read the entire thread at 
http://www.gossamer-threads.com/lists/mythtv/users/268198#268198 , and 
if you can answer the questions in that thread, please do so either here 
or there.  Just noticed you're the same guy who started that thread...

The most important suggestions:
    a) use the DISH network LIRC configuration at 
http://www.mythtv.org/wiki/index.php/DISHNetworkLIRCConfiguration
    b) make sure the user running irsend and the user running lircd both 
have permissions to the RTC (may require modprobe rtc)
    c) use a kernel with at least 300Hz timing or, even better, 1000Hz 
timing
    d) if you're using a kernel with dynamic ticks, try one without (or 
vice versa)
    e) if possible, use a preemptible kernel (ideally with preempt the BKL)

Note, though, that this issue appeared out of nowhere for me on a Linux 
2.4 system (before kernel Hz were configurable, before dynamic ticks, 
and before preempt the BKL on a system with a properly configured RTC 
that had worked for over 2 years and on which I hadn't made /any/ 
changes for at least 2 months before it started happening).  That's why 
I chalked it up to hardware failure, but I didn't look into it because I 
was going to be dropping DISH "soon."

I think the cheap solution is buying a different transmitter with its 
own timing circuitry.  If you're willing to do some work, though, you 
may be able to figure out what has changed (in DISH or in LIRC) and fix 
it.  With the end of season basically here, you may not miss anything 
too important in the meantime, but you'll have to decide whether 
reliability is worth $20-$40 for a new tranmitter or whether making the 
(probably serial) transmitter you have work reliably is worth the X 
number of hours you'll spend (where X could easily reach triple digits).

Mike


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