Hans,

Thanks for the clues, I did disable hyperthreading in the bios and passed
noht to the kernel. I am playing back a movie right now. It will take a
while to see if this prevents the freeze. If it plays to completion without
freezing I will call it a success.

Of course this does nothing to fix the undelying bug in processing with a
true SMP configuration but it will work to solve my basic problem.

I at first was wondering how this was going to work since I had many modules
compiled against the SMP configuration but everthing seems to work without
having to recompile so far so we will just wait and see!

Steve

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Hans Verkuil
Sent: Saturday, November 19, 2005 9:21 AM
To: Discussion list for development of the IVTV driver
Subject: Re: [ivtv-devel] ivtv framebuffer is broken with PVR350


On Saturday 19 November 2005 18:09, Steve & Laurie Sanders wrote:
> This is a big clue! I think. I believe it supports my suspicion that
> the DMA linked list programming might get occasionally clobbered with
> SMP kernels. In your case you have two physically separate processors
> so you can remove one. When the kernel boots it will only see one so
> there is never going to be another processor banging away with an
> opportunity to collide with whatever goes wrong in DMA transactions.
> In my case, I have a hyper threading enabled P4 processor which is
> actually two processor cores on one socket so I can not do this
> experiment. My only option is to load a plain vanilla non SMP kernel
> instead. That means I also have to recompile and install many modules
> which I built for SMP kernel. I am thinking of just building another
> whole image on a differend HDD. It might be easier!

Isn't is possible to turn hyperthreading off in the bios? Also, I
remember seeing a 'noht' kernel option that turns off Hyperthreading
support in the kernel.

> I think what you are seeing when you press "save position" is the
> pointers being shifted to a new index in the video stream buffer and
> programming a new DMA transfer starting at the new index thus fixing
> the corrupt DMA link list. I do not have clue how to go about
> debugging this myself. I would be happy to load gdb and look at it if
> someone who knows what they are doing can give some direction.
>
> Sounds to me like we just have way more processing power available
> than the driver can handle! of course it only seems to be a problem
> when X is running along with mythtv. Like you I would really like to
> be able to exploit my extra processor but I may just have to
> downgrade my media center to a single processor till we can get this
> figured out.

No, it looks like classic smp problems, hard to fix if you don't have a
dual cpu. And I haven't. None of the main developers have such a
computer, so I am not surprised that there are smp bugs.

        Hans

>
> Steve
>   -----Original Message-----
>   From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] Behalf Of Ricardo Lugo
>   Sent: Saturday, November 19, 2005 8:24 AM
>   To: Discussion list for development of the IVTV driver
>   Subject: Re: [ivtv-devel] ivtv framebuffer is broken with PVR350
>
>
>   I have the same problem as Steve with my dual-processor & PVR350
> TV-out setup.
>   I usually get freezes within the first 10 minutes of playback.
>
>
>   When I remove one of my processors (same vanilla 2.6.14 kernel w/
> SMP & PREEMPT) this doesn't happen.
>
>
>   Curiously, when it freezes during playback in myth, if I press
> "save position," it saves the position, displays some stuff on the
> OSD, and then unfreezes & continues playback 10 minutes downstream
> (hopefully this means something to someone).
>
>
>   John, I tried your tests (an hour each) and here are the results:
>
>
>   1) Decoder-only: no crashes
>   2) Decoder & Encoder: no crashes
>   3) Decoder & FB updates: no crashes
>   4) Decoder & Encoder & FB: no crashes
>
>
>   So, inconclusive...
>   If there's any other tests you would like for me to run, I offer up
> my time to help diagnose.
>
>
>   -Rick
>
>
>   On Nov 12, 2005, at 2:34 PM, Steve & Laurie Sanders wrote:
>
>
>     I have been posting about freezing playback and ivtv-osd
> warnings, and ivtv DEC warnings in the ivtv-users list sinsce I am
> using 0.4.0 stable. I tried to provide enough detail to solicit some
> help but nobody has responded. I think I have done enough debugging
> to narrow the problem down to the ivtv driver and based on that have
> filed abug report (#53) in the Trac system.
>     Ticket URL: http://ivtvdriver.org/trac/ticket/53
>
>     You can find my previous posts to ivtv-users here:
>
>
> http://www.ivtvdriver.org/pipermail/ivtv-users/2005-November/000184.h
>tml &
>
> http://www.ivtvdriver.org/pipermail/ivtv-users/2005-November/000239.h
>tml If I need to post somewhere else, let me know where. If you need
> more infomation "". Yesterday I went so far as to disable tvout, and
> not load ivtv-fb and just playback directly to my monitor without
> using framebuffer or xdriver. When I did this I was able to playback
> a two hour movie without any freezes. This to me indicates the
> problem is somewhere in either the framebuffer or xdriver interface.
>     I would like to do whatever I can to support the development of
> this project, I am willing and able to capture any kind of debug
> information that might be requested. Are there any develpers out
> there that have any interest in this failure? It may be specific to
> smp cores, I don't know how many are developing systems with smp
> processors.
>     Regards,
>     Steve
>
>     Regards,
>     Steve
>
>     _______________________________________________
>     ivtv-devel mailing list
>     [email protected]
>     http://ivtvdriver.org/mailman/listinfo/ivtv-devel

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