[mythtv-users] Firewire stability/reliability DCT6200

[Suresh Randawa]

Mark Hutchinson wrote:
> I seem to be having a great deal of erratic and unstable behavior on 
> Firewire and my DCT6200
> 
> Using CentOS 5.1 ( with plus kernel for firewire support ), I can 
> reliably see the DCT6200 with plugreport.  So firewire is working fine.
> The port is always 0 but the node goes between 0  and 1.  This is also 
> fine, though it requires messing with mythtvsetup on each reboot which 
> seems not very elegant.
> 
> The problems I am hoping to solve are the erratic nature of this once I 
> get it configured.  Some times I seem to get data from firewire with 
> test-mpeg2, and other times I just get a zero length file.  If it is 
> working, I have it going through myth, I change channels, sometimes it 
> works, sometimes it hangs for a minute and then to the main Myth Menu.  
> After which I have to go through the setup again, reboot, etc......
> 
> I know the mechanics are working, sometimes I can get all channels 
> coming to Myth fine, change channel, record etc....
> This solution will work very well, if I can just get it to work almost 
> all of the time, now it is almost none of the time.
> 
> Any advice on what I can do to try to stabilize this? I have seen 
> references to priming? 
> Things to check, diagnostics?
> 
> After a couple of full days with this, I am really looking for some 
> assistance to fix it.
> 
> Thank you.

I have been experiencing that with my DCT6200 as well from the very
beginning. I have found that some firewire card-chipset combinations
work better than others. I have also found that certain channels are not
recordable at all, and I do not think this has to do with the channels
being encrypted as some channels that I know are encrypted QAM over the
cable are recordable over firewire.

The best results I get are after "priming" the port with
firewire_tester. I run the following until the port comes up (change for
your own port numbers):

firewire_tester -B -P 0 -n 1

Running this periodically can ensure more reliability. One thing I have
found is that after watching live TV over the firewire connection, and
changeing a few channels, the box eventually stops working with mythtv.
Priming the cable box seems to do the trick. If the cable box is set to
one of the channels that are never recordable, firewire_tester never
works. It only works when the box is on a channel that is recordable.
This is purely from my experience.

Another step I take is to run a cronjob at 25 and 55 of the hour that
calls firewire_tester to make sure the port is ready if there ever is a
recording coming up.

The firewire port on the DCT6200 that I have is temperamental at best,
but it maybe just that particular box, or that some of those STBs just
were not built right. After all, that port is only there because FCC
regulations. But with that being said, I have recently been getting very
reliable recordings from that STB.