[AG-TECH] System freezes sending video on Linux w/ IVC-200 capture card

[Christoph Willing]

On 21/04/2009, at 3:47 AM, Andrew Ford wrote:

> Hi Chris,
>
> After some testing we've seen this happen with multiple IVCs and  
> multiple machines - at any rate, we don't have any more spare linux  
> boxes to test with. I have a feeling it might be related to Ubuntu's  
> CPU frequency scaling though, as I've never seen it freeze when I  
> manually set it to use the maximum clock speed. What are the clock  
> settings on your machine?


Andrew,

Did you roll your own kernel? When I tried to add the cpu frequency  
scaler applet, it reports that I don't have it set in the kernel -  
since I try to keep our build machines as standard as possible (i.e.  
only latest supplied kernels) and if frequency scaling is working for  
you, I'm guessing you have a non-standard kernel. In that case I  
suggest you revert to a standard kernel to test whether the freeze  
effect goes away. Either the  frequency scaling itself or the change  
of some other kernel option may be causing the freeze effect;  
reverting to a standard kernel could rule those changes out as the  
cause.


> Also, as a side note, does anyone know how to set the default on  
> boot to be max clock speed? The gnome-power-manager menu in gconf- 
> editor doesn't have any options for setting CPU frequency.

In my case, without frequency scaling enabled in the kernel, the  
scaler applet works in read only mode. From that, I could see that the  
clock setting is set to 100%.

BTW it looks from the applet like the frequency scaling could be set  
to different values on different cores of a multicore machine - that  
may also contribute to the freezing.


chris


> 2009/3/29 Christoph Willing <c.willing at uq.edu.au>
>
> On 26/03/2009, at 4:58 PM, Christoph Willing wrote:
>
>
> On 26/03/2009, at 3:34 AM, Andrew Ford wrote:
>
> Hi,
>
> For a while now we've been seeing hard freezes (ie, trying to kill  
> the X server does nothing) on one of our Linux machines when it  
> tries to send video via an IVC-200 cap card. It tends to occur more  
> frequently when the load is heavier - attempting to send 2 or more  
> 720x480 mpeg4 or h.264 streams causes it to freeze within 5-10  
> minutes, 4 h.261 videos make it freeze in about half an hour, and 2  
> 261 videos makes it last about 2 days. dmesg and /var/log/messages  
> don't give any clues. Other types of load don't seem to cause  
> freezes, and I ran memtest86 overnight with no errors. Originally  
> the machine was Ubuntu 8.04 64-bit, then 8.10 64-bit, then 8.10 32- 
> bit, and the problem was seen in all 3. In all cases it was running  
> the UQ-provided AG 3.2beta with the stock VideoProducer services. I  
> know there was a bttv driver deadlock issue in kernels pre-2.6.24,  
> but this is running kernel 2.6.27 so that shouldn't be the problem.
>
> Also when sending video on that machine occasionally the stream  
> would start to flicker, flashing an old frame alternating with the  
> current output of the camera. Has anyone seen either of these issues  
> before?
>
>
> Andrew,
>
> I just installed a 32bit Ubuntu 8.10 on the UQVislab node's video  
> capture machine. I've been running 2x mpeg4 streams and an h261  
> stream for over two hours. I just powered the machine down to  
> confirm it is actually an IVC-200G card (it is). After the restart,  
> I've now configured it to run with 3x mpeg4 streams. These are full  
> PAL streams 704x576. Its been running for nearly 10 minutes now -  
> will leave it running overnight (in the APAG lobby, if you want to  
> check on them) and report back. Based on the previous successful 2  
> hour test, I think this 3 large streams test will be OK too.
>
>
> Andrew,
>
> We've now had this setup (32bit Ubuntu 8.10 with IVC-200G streaming  
> 3x mpeg4 streams @ 704x576) running continuously for over three days  
> now without any discernible problem. That result suggests a hardware  
> issue with your capture card (or even the machine itself).
>
>
> chris
>
>
>
>
> You could try reseating the card - maybe some dust or contact  
> oxidation is creating some bad effect? Do you have any similar  
> capture cards lying around you could temporarily replace the IVC  
> with? That may indicate whether you have a card fault or machine/OS  
> fault.
>
>
> chris
>
>
> Christoph Willing                       +61 7 3365 8316
> QCIF Access Grid Manager
> University of Queensland
>
>
> Christoph Willing                       +61 7 3365 8316
> QCIF Access Grid Manager
> University of Queensland
>
>

Christoph Willing                       +61 7 3365 8316
QCIF Access Grid Manager
University of Queensland