[mythtv-users] Re: Machine lock ups, I need help

[Craig O'Shannessy]

I have a bttv card as well, I was getting kernel oops's with it (with a 
KT133).

Actually, I remember one test that I could reproduce.  Just writing to the 
hard disk very fast seemed to kill it.

try this 

[root at yourbox /]# cat /dev/zero > testfile

See if this crashes your machine after running for a couple of minutes.  
If not, try it whilst watching TV using xawtv.  This should give your bus
a good thrashing without Myth.  This test wouldn't reliably crash my box,
but it would do it regularly.

Also, Myth does hit the bus much harder than live tv because :

- The sound gets recorded rather than streaming into the soundcard (via a 
cable), and straight back out, without hitting the bus if your using XAWTV 
(at least that's my understanding).  Myth actually records the sound 
(which is why you have to mute the line in output).

- It's recording, even whilst watching livetv (although possibly not for 
you with your large RAM and small ringbuffer), so large amounts of data 
and IDE requests are also competing for the BUS.

At least thats my understanding.

Anyhow, I wasted MANY hours on the KT133 box before giving up.  Your time 
is worth SOMETHING I'm sure ;)

Also, there is plenty of evidence of other non-myth KT133 crashes. This 
chipset doesn't have a good reputation!

http://groups.google.com.au/groups?q=kt133+crash

Craig


On Monday 08 December 2003 06:50, Dhiraj Gaurh wrote:
> Craig O'Shannessy wrote:
> >Hi,
> >
> >I don't support your motherboard has a KT133 chipset?
> >
> >http://mythtv.org/pipermail/mythtv-users/2003-September/014216.html
> >
> >I had the same symptoms, same CPU, and I bought a new 'puter to use,
> >booted up using the original hard disk, and haven't had a crash
> > since
> >
> >If you have this chipset, I think that's your problem.
> >
> >Hope this helps
> >
> >Craig
> >
> >
> >
> I have the FIC AZ11E which also uses KT133 chipset. I have never had
> kernel Ooops but my recording part is not working yet. If bttv has
> problems with KT133 then why have I been watching TV for the last two
> years using xwtv without any problems. How does bttv know that I am
> recording or playing, it should be the same thing, this is just an
> application level differnce. I have used the vcr program to record
> shows in the past without any problems. If you can watch TV on this
> chipset then it is perfectly possible to record too.
> I am using RH 7.2 with AMD T-BIRD 950 MHZ
> My mythtv recording  part is not working because of some software
> problem which I need to fix, it doesn't crash my machine. It just
> doesn't record, nothing happens. I am not going to believe that this
> KT133 bug surfaces only with myth and not with vcr !
> A computer costs a lot of money. I can't afford to buy a new computer
> because some particular feature of one application is crashing. Why
> don't you use mythtv to watch live tv and use vcr to record in your
> old computer. Should work on yours if it works on mine. If KT133 is
> at fault, that is.
> You murdered your old friendly computer  :)


The problem with the KT133 chipset has nothing to do with bttv.  If you
have a bttv card, as you seem to, then there is no issue.  The problem
occurs if you have an ivtv card (PVR-x50, M-179).  There is a known
chipset bug (or 'quirk', if you prefer) that causes problems when using
the ivtv driver.

Incidentally, Myth does not use 'bttv' for playback... since
playback-only in Myth doesn't involve the tuner card.  The bttv/V4L
driver is only used in Myth for recording or LiveTV.  Playback is done
solely through your video card using X (Xv/XvMC).  So it is entirely
possible for problems to arise during recording that don't occur during
playback only.

Craig was only offering a helpful suggestion... there was no need to be
rude, especially since it seems you're not really clear on how Myth
actually works.

-JAC