[mythtv] 0.21 Firewire bus reset every 60 seconds?

Derek Atkins warlord at MIT.EDU
Wed Oct 1 14:22:57 UTC 2008

"Eric Smith" <erictsmith at gmail.com> writes:

> On Mon, Jun 16, 2008 at 10:49 AM, Derek Atkins <warlord at mit.edu> wrote:
>     Hi,
>     Derek Atkins <warlord at MIT.EDU> writes:
>     > Here's an example of the backend log between the 60-second "okay
>     period":
>     >
>     > 2008-06-11 08:43:37.498 LFireDev(000E5CFFFE5AF9A5): SignalReset(86->87)
>     > 2008-06-11 08:43:37.553 LFireDev(000E5CFFFE5AF9A5): SignalReset(86->87):
>     Updating device list -- begin
>     > 2008-06-11 08:43:37.815 LFireDev(000E5CFFFE5AF9A5): SignalReset(86->87):
>     Updating device list -- end
>     > 2008-06-11 08:43:37.917 LFireDev(000E5CFFFE5AF9A5), Warning: No Input in
>     50 msec...
>     > 2008-06-11 08:44:37.501 LFireDev(000E5CFFFE5AF9A5), Warning: No Input in
>     100 msec...
>     > ...
>     After updating libraw1394 from 1.2.1 to 1.3.0 this kind of error seems
>     to have been reduced..  But it also seems to be a problem if the
>     firewire broadcast bus isn't completely synched.  For example, the
>     myth box was rebooted yesterday and then the first recording had
>     this issue.  But then I reset the bus manually using firewire_tester
>     (which, by the way, took two or three tries before it synced!)..
>     and then my recording this morning was fine.
>     So something weird is still going on, but at least the libraw upgrade
>     seems to have helped.
>     Any other suggestions?  My next step is to setup a script to run
>     firewire_tester on boot-up to make sure the bus is stable before
>     mythbackend runs.
>     -derek
> I also see this issue, somewhat infrequently, but enough to be a problem. 
> Does anyone have any suggestions on things I could check to resolve it?

I converted over to an external channel change script that runs
firewire tester on every channel change to force a bus synchronization.
This might reset the bus, so it might not work right if you have
multiple firewire devices.   The script is based on the script
from http://www.mythtv.org/wiki/index.php/User:Steveadeff#6200changer.sh
but I had to make a few changes to get it working right for me.

Since I've changed to this script I haven't lost a single recording,
and the number of times I get the sequencial bus resets from myth
has been reduced dramatically (although not completely eliminated --
I've still seen it happen once or twice).

Another side effect of this script is that LiveTV times out when
using this tuner.  Apparently the script takes "too long" and
LiveTV gives up too quickly.  I haven't looked into extending
the timeout.


       Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
       Member, MIT Student Information Processing Board  (SIPB)
       URL: http://web.mit.edu/warlord/    PP-ASEL-IA     N1NWH
       warlord at MIT.EDU                        PGP key available

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