[mythtv-users] System crashes on start of DVB-S recording

Jelte Veldstra jelte.veldstra at gmail.com
Mon Feb 9 12:57:01 UTC 2009


On Mon, Feb 9, 2009 at 1:27 PM, Bruce Taber <b.taber at comcast.net> wrote:

> Jelte Veldstra wrote:
> > This issue really drives me mad and I was wondering if others have
> > experienced the same.
> >
> > I have built a dedicated backend based on CentOS 5 (with DVB support
> > from centos.plus kernels) and MythTV 0.21-fixes. It is currently fitted
> > with two Hauppauge Nova-S (budget) DVB-S adapters. Encrypted channels
> > are decrypted using open-sasc-ng and a subscription card in a phoenix
> > smartcard reader.
> >
> > This setup works quite well but every now and then (~ 1 in 100
> > recordings) I have this setup hardlocking on me as a recording is
> > started. After restarting the system and looking into the logfiles there
> > is nothing that hints what happened that made it crash. It looks as if
> > the power plug was pulled as syslog shows nothing on the Linux level.
> > The backend log only shows the line that indicates a recording is
> > started and nothing since. The sasc-ng log shows no attempt of the
> > backend connecting to it for this recording. The system has had its
> > share of stress tests to rule out memory, power or overheating problems
> > and has shown no such issues.
> >
> > As MythTV and sasc-ng run as non-privileged users it seems like
> > something is going on on kernel and driver level. This thought is
> > enforced as it only seems to happen with stv0299 based adapters (such as
> > the Nova-S). Having used a single Twinhan 1030A DVB-S adapter (dvb-bt8xx
> > based) for a while never failed on me. And when I mixed both types (I
> > really want a twin-tuner system) it would occasionally crash on the
> > Nova-S but never on the Twinhan.
> >
> > So somehow it seems related to the hardware, but as I tried three
> > different stv0299 based tuners, it's not a faulty adapter is seems but
> > rather a driver issue. If I could find a second 1030A then I would try
> > that for sure, but I havent been able to find one, plus I'd really like
> > to understand what's going on here. Searching linuxtv.org
> > <http://linuxtv.org> mail archives doesn't provide answers on that.
> >
> > Googling for it revealed some possible hints. One suggestion was that it
> > could be multirec in combination with open-sasc-ng. Others have found
> > that multirec not being 100% working with open-sasc-ng but had no
> > crashes. To rule is out I have disabled multirec, but still have had
> > crashes. Another suggestion was that a race condition could arrise
> > between software RAID5 code and the DVB subsystem (would explain why
> > there are no kernel messages during or after the crash). As I used soft
> > RAID5 I have since removed that configuration from my setup, but still
> > no luck.
> >
> > So I have spent quite some time googling and trying out what I found
> > there, but no luck yet. I'm runnning out of ideas and wondered if other
> > MythTV users have had similar issues or found a pattern. So far I cannot
> > reproduce it and the only pattern so far is that it only happens at the
> > start of a recording (never during or outside recordings) and on stv0299
> > based adapters.
> >
> > If you recognise this or have any pointers for me to try, please share.
> >
> > Thanks in advance,
> >
> >
> > Jelte
> >
> >
> > ------------------------------------------------------------------------
> >
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> > mythtv-users at mythtv.org
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> My system suddenly started this same type of behavior. The problem was
> finally traced down to a faulty onboard Ethernet port. Disabling the
> Ethernet in the BIOS and installing a separate card eliminated the
> problem completely.
>
> Bruce
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>


Hello Bruce,

Thanks for your input. What led you to this conclusion and what Ethernet
chip was the faulty one? My PCI slots are taken so I cannot easily try it
myself. Where there messages in logfiles that hinted issues with the
Ethernet port or was the Ethernet traffic poor? I have already replaced this
motherboard (for different reasons) and it now has a different Ethernet
chip. As far as I can tell it's working just fine, but perhaps there are
conflicts with certain chips.

Regards,


Jelte
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