[mythtv-users] Can I pass parameters to my channel changing script?

Patrick Oglesby octoberblu3 at gmail.com
Mon Apr 30 14:32:14 UTC 2012


On Mon, Apr 30, 2012 at 7:09 AM, Craig Huff <huffcslists at gmail.com> wrote:
> On Sun, Apr 29, 2012 at 3:12 PM, Gary Buhrmaster
> <gary.buhrmaster at gmail.com> wrote:
>> On Sun, Apr 29, 2012 at 19:05, Patrick Oglesby <octoberblu3 at gmail.com> wrote:
>> ....
>>
>> You have to do locking, otherwise you can have a race condition.
>>
>> ....
>
> I have been using the script "change-channel-lirc.pl" for three of my
> Comcast DTAs.  I had not considered the issue of a race condition
> before now and in over a year of usage I have seen no evidence of such
> an issue.  I don't see anything in this script to prevent this
> problem, but scanning through my mythbackend.log files, it looks like
> the cases where multiple recordings start at the same time is handled
> by mythbackend issuing the tuning commands in sequential order, rather
> than concurrently.  Have I just been lucky (perhaps due to using a
> single-core processor for most of the time and only recently upgrading
> to a dual core CPU) or is the risk of a race condition not so
> clear-cut?
>
> Craig.


If you have separate devices for each STB, then you will never have
this problem.  It can happen when you have 2 or more transmitters from
a single lirc device, like many of the mceusb receiver/transmitters
out there.

- Patrick


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