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R5A12 Live TV freezing and then screen goes black... reboot.
http://forum.linhes.org/viewtopic.php?f=6&t=4088		 Page 1 of 1
Author:  montanaq [ Wed Apr 06, 2005 12:02 pm ]
Post subject:  R5A12 Live TV freezing and then screen goes black... reboot.
I've done a fresh R5A12 install and it was pretty stable at first, but now about once or twice a day, Audio and Video will freeze with a static image of the TV show on the screen. When we have waited, the screen actually goes black and trying to restart X with Ctrl+Alt+BkSpace does not work. It froze one while watching a video through an SMB connection, but that may have been a fluke.

Is anyone else getting freezups?
I've not upgraded/changed ivtv drivers yet.

Someone recommended pausing live TV for 30 sec's to prevent a freeze in the future. Has that helped anyone? I will gave it a try this week.

P.S. I'm using an Nvidia card with drivers that came with R5A12.
Author:  tjc [ Wed Apr 06, 2005 12:25 pm ]
Post subject: 
Does it happen when watching live TV on the same channel for long stretches? Say for about the length of time that would cause the live TV cache to wrap? If so check your logfiles (/var/log) for messages about safe_read failures. It seems to be fairly common...
Author:  montanaq [ Wed Apr 06, 2005 5:39 pm ]
Post subject: 
Thanks for the tip.
I did this on the files in /var/log/:
cat * | grep safe_read
and in each of the dir's in /var/log/

...but no dice....

if I was getting that message what should I do about it (if there is anything I can do about it)?
Author:  tjc [ Wed Apr 06, 2005 7:25 pm ]
Post subject: 
Do the other indicators match? If not it may be something else. Sadly, there's not much you can do about it other than making the cache partition bigger to defer the problem or changing the channel occasionally.
Author:  bshroyer [ Wed Apr 06, 2005 8:58 pm ]
Post subject: 
When I read the top parent, I didn't interpret montanaq to mean that the freezes were happening on watching live tv. Can you confirm this, montanaq?

The reason I'm butting in here is that the symptoms sound very similar to my own experience, which I had attributed to faulty hardware/drive/ISO on my end. I'm interested to see how this resolves...
Author:  tjc [ Wed Apr 06, 2005 10:24 pm ]
Post subject: 
Well, that basic diagnostic question _is_ what I was trying to ask... ;-) The initial description was a bit sparse...

It's kind of a pet peeve that folks around here have heard me rant about before, but why is it so hard to get people who are having problems with their system to provide anything like enough detail to help diagnose it? You try leading questions ("Is is a sharp pain or a dull pain?" "Is it a grinding noise or a squeak?" "Does it happen when you're watching live TV after a couple hours?") and at least half the time you don't get an answer. I supposed doctors and auto mechanics have the same problem but at least they're usually go the "patient'" right there in front of them...

BTW - the post subject actually says "R5A12 Live TV freezing ..." which is why I started down that path...
Author:  montanaq [ Thu Apr 07, 2005 6:17 am ]
Post subject: 
I'm sorry if you feel I didn't give enough info. I thought I had. Part of the problem is that I'm not the main user of the box, and haven't seen most of the freeze-ups. I'm try to get as much info as I can.

The HDD I'm using is a 120 Gig (I think a Maxtor) that I bought around Christmas. It's pretty new, but I realeaze that doesn't always mean it won't have problems.

What indicators are you refering to? I'm sorry... I don't understand what you are asking.
Do you mean: mythtv freezing when watching live TV on the same channel for long stretches? I have an 8 gig cache partition and a pvr-250 doing hardware encoding. I think that works out to about 4 hours. I'll double check with my wife but you may be on to something,

As suggested somewhere in the forum, I've recently (this morning) tried to go into mythtv-setup and lower the size that mythtv uses for cache to 1 gig less than what is actually partitioned.

I'll report back on how things are going.
Thanks for your help.
Author:  drworm21 [ Thu Apr 07, 2005 5:15 pm ]
Post subject: 
Try turning off XvMC. I was having the same problems as you and everything seems to have cleared up when i turned it off.
Author:  tjc [ Thu Apr 07, 2005 7:14 pm ]
Post subject: 
drworm21 wrote:
Try turning off XvMC. I was having the same problems as you and everything seems to have cleared up when i turned it off.

Always a worthwhile suggestion. ;-) If you don't absolutely need XvMC it's best to avoid it. It's definitely not the worlds most stable and reliable software.
Author:  tjc [ Thu Apr 07, 2005 7:25 pm ]
Post subject: 
montanaq wrote:
I'm sorry if you feel I didn't give enough info. I thought I had. Part of the problem is that I'm not the main user of the box, and haven't seen most of the freeze-ups. I'm try to get as much info as I can.

My grumble was that it seemed like the questions got completely ignored. I asked "dark or light" and the response was "three wombats". :shock: Huhn?

It always makes me feel like I'm in the old joke about how many surrealists it takes to change a light bulb...
Author:  montanaq [ Sun Apr 10, 2005 4:14 pm ]
Post subject: 
Thanks for your suggestions.

XvMC... I'm sure that I intentionally did NOT install it (I've read about all the problems people have had with it), but I may have goofed, and accidently installed it, or it got installed despite my choosing not to. How do I verify that it is enable in my Myth install?

I spent some time testing and have found the following:

I set the myth frontend to live TV and it froze not too long afterwards.
I got these error messages in my backend log file:

005-04-08 07:37:26.837 Changing from None to WatchingLiveTV
QSettings: error creating /.qt
QSettings::sync: filename is null/empty
(the above two lines get repeated a few times)

and further down:

2005-04-08 07:58:29.182 Changing from None to WatchingLiveTV
ERROR: file I/O problem in safe_write(), errcnt = 1: No space left on device
ERROR: file I/O problem in safe_write(), errcnt = 2: No space left on device
ERROR: file I/O problem in safe_write(), errcnt = 3: No space left on device
(54 Megs... later the log file ends)

I have also determined the following:
I went to live TV and from an ssh connection went in the /cache directory. I started typing:
ll -hR
...and I watched the results.

The ringbuf1.nuv steadly increased. That's good, and that's what I expected it to do.

When I changed channels shorlty after going to live TV the ringbuf1.nuv kept growing. good,

When I waited for quite a while and the ringbuf1.nuv was atleast a Gig I tried changing channels.... the ringbuf1.nuv stopped growing, but the time stap on the file kept getting updated. I then proceeded to delete the ringbuf1.nuv file (hoping it wouldn't crash the frontend, and it didn't) and it never got recreated and I was still able to rewind live TV. Strange? Maybe it never got truely deleted becasue Myth had it locked.

If I exit it out of live TV and then go back in, it recreates the ringbuf1.nuv file if it's gone, and starts a fresh file without the non-gowing problem if I had the non-gowing ringbuf1.nuv problem.

That was all the time I had for testing.

I'm hoping someone can make sence of some of this. Feel free to ask me to test something or get further/clearer info.
Author:  tjc [ Sun Apr 10, 2005 9:21 pm ]
Post subject: 
Part of the explaination is that deleting an open file doesn't really make it go away. The inode can't be released while any process still has it open. The fixed size file is odd however... Aha! I've got it, rather than wasting time deleteing or truncating the file when you change channels it just seeks back to the beginning and starts overwriting the existing file... The size isn't really fixed, it just takes as long again for it to start growing...

From the logged errors it's pretty clear that the ring buffer file is exceeding the amount of space left on the partition for some reason. Here is the next experiment, run this loop from a shell window while watching live tv (put it on one channel and leave it):
Code:
while true ; do date ; df ; ls -al /cache/cache/ ; sleep 30 ; done
Author:  montanaq [ Wed Aug 31, 2005 7:18 pm ]
Post subject:  problem resolved!
After months and months of tinkering, I solved my freezup problems.
I moved my pvr-250, and HDD into a new computer and started fresh.
I am no longer getting the freezups. The new computer is of the same caliber but it is a Dell and my old computer had a crappy ECS mainboard that a friend gave me.

Lesson learned...try and use half-a$$ decent hardware.

Thanks for everyone's help and patience.
Author:  Greg Frost [ Wed Aug 31, 2005 7:50 pm ]
Post subject: 
I used to get freezups before I changed the memory timings in the bios. memtest detected errors with the default memory speed. After slowing the memory clock down, memtest reported no errors and my lockups went away.
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