[mythtv-users] Myth having problems communicating across master/slave backends

[Chad]

Hello!

I have been struggling trying to work out a bug that is keeping the
man down for quite a while.  I've searched the archives, and tried a
few different ideas (like reinstalling everything from X.org to nvidia
drivers, to myth) but nothing changes my problem(s) (the (s) is
because I believe they are all related...)

Ok, to summarize:

When I connect to mythweb, I do so by going to the Master BE's URL:
http://mbe/mythweb

This works out, I get the program listings just fine.  I can hop
around to a few of the tabs, but when I click on backend status, it
dies and gives me the following error:
------------------------
User Notice at /var/www/localhost/htdocs/mythweb/includes/mythbackend.php,
line 159:
Unexpected response to MYTH_PROTO_VERSION 'MYTH_PROTO_VERSION 15':
Fatal Error at /var/www/localhost/htdocs/mythweb/includes/mythbackend.php,
line 32:
Unable to connect to mythbackend, is it running?

The system administrator has been notified and the problem will be
remedied shortly.
------------------------------

In the browser window.  

Related summary of another error:
When I fire up mythfrontend (on a remote frontend/slave backend
system) I will sometimes get an error in the startup dialogue that
coincides with the above error about MYTH_PROTO_VERSION.  However, in
mythcontext.h (which on my system is
/usr/include/mythtv/mythcontext.h) the version is indeed 15, which
matches with mythweb's version in /mythweb/includes/mythbackend.php

So, let me explain my setup, and tell you what I've tried and what
progress I have made, and where.

I have 2 backends.  They are both also frontends, and are both running
Gentoo.  The master is an AMD64, has 2 bt8x capture cards, and works
fine by itself.  The slave is an AMD 2200+ has 1 saa7134 and 1
pchdtv3000 (using DVB) card.  It also works fine by itself (as a
slave, never tried switching which is master and which is slave). 
However, the problems begin to arise if I choose a recording that was
captured on the remote box (whether it be the slave has the file, or
the master).

Recently, I tried to make progress by troubleshooting this with
mythweb, and it seems I may have gotten somewhere.

I generally access mythweb on the master backend.  As noted above,
this works until I click something that must access the slave backend
data, and then dies with the above info.
So I decided to setup and access mythweb on the slave using the
slave's implementation (meaning I used the slave's hostname in the
url).  It errored out immediately.  I thought that was odd since I can
usually get the first screen at least.  So I edited MYTH_PROTO_VERSION
in mythweb/includes/mythbackend.php to 14 (it's set at 15 just as
every other one on the system is) saved, and went the URL again.  This
time I got the error telling me mythweb=14 mythtv=15 version mismatch.
 Woohoo!  So I edited it back to 15, and SUCCESS!!!...  For a minute. 
As soon as I clicked on backend info, it returned with the error noted
earlier:
-------------------
User Notice at /var/www/localhost/htdocs/mythweb/includes/mythbackend.php,
line 159:
Unexpected response to MYTH_PROTO_VERSION 'MYTH_PROTO_VERSION 15':
Fatal Error at /var/www/localhost/htdocs/mythweb/includes/mythbackend.php,
line 32:
Unable to connect to mythbackend, is it running?

The system administrator has been notified and the problem will be
remedied shortly.
-------------------------

And now I can't do anything to make it work.  

BUT it seems that I may have tracked down the culprit, or at least
narrowed my search to the slave backend.

Something I've noticed since that may give a clue to what's going on:

I have to spawn myth by calling it directly (as root) with:
# /usr/bin/mythbackend -d -l /var/log/mythtv/mythbackend

I do this on both machines because the init script doesn't work out
the box, and... (it's another story)...
On the machine that works fine, the master backend, I get 1 instance
of mythbackend:
-----------------
ps aux | grep myth
root     13119  0.0  7.5 249988 76932 pts/3    Sl+  Aug17   0:36 mythfrontend
root     14775  3.2  1.7 183440 17880 ?        Ssl  03:38   0:00
mythbackend -d -l /var/log/mythtv/mythbackend
masterc  14788  0.0  0.0   2700   520 pts/0    R+   03:38   0:00 grep myth
---------------------
But on the slave I get quite a bit of multiples:
---------------------
root      1906  0.0  3.6  63716 18832 ?        S    03:39   0:00
mythbackend -d -l /var/log/mythtv/mythbackend
root      1908  0.0  3.6  63716 18832 ?        S    03:39   0:00
mythbackend -d -l /var/log/mythtv/mythbackend
root      1910  0.0  3.6  63716 18832 ?        S    03:39   0:00
mythbackend -d -l /var/log/mythtv/mythbackend
root      1911  0.0  3.6  63716 18832 ?        S    03:39   0:00
mythbackend -d -l /var/log/mythtv/mythbackend
root      1912  0.0  3.6  63716 18832 ?        S    03:39   0:00
mythbackend -d -l /var/log/mythtv/mythbackend
root      1913  0.0  3.6  63716 18832 ?        S    03:39   0:00
mythbackend -d -l /var/log/mythtv/mythbackend
root      1914  0.0  3.6  63716 18832 ?        S    03:39   0:00
mythbackend -d -l /var/log/mythtv/mythbackend
root      1915  0.0  3.6  63716 18832 ?        S    03:39   0:00
mythbackend -d -l /var/log/mythtv/mythbackend
root      1916  0.0  3.6  63716 18832 ?        S    03:39   0:00
mythbackend -d -l /var/log/mythtv/mythbackend
root      1917  0.0  3.6  63716 18832 ?        S    03:39   0:00
mythbackend -d -l /var/log/mythtv/mythbackend
root      1918  0.0  3.6  63716 18832 ?        S    03:39   0:00
mythbackend -d -l /var/log/mythtv/mythbackend
masterc   1921  0.0  0.0   1500   508 pts/2    S+   03:39   0:00 grep myth
------------------------------

During both of these queries, nothing is happening (nothing is being
recording, nothing is being flagged or transcoded by mythbackend on
either machine).

So for now, I'm blaming the multiple instances.  But...  I don't know
how to get rid of them (I do know how I can kill -9 their PID) on a
longterm basis, or why they are even spawning.

Any ideas are very welcome.  As noted above, I have tried uninstall
everything completely and reinstalling everything completely that is
remotely related to myth, but the result doesn't change.

Thanks for any ideas, and I am very open to obvious pointers!  :)

Thanks!