On Wednesday 07 December 2005 04:26, Geoffrey Kruse wrote:
> > On Saturday 26 November 2005 07:30, Geoffrey Kruse wrote:
> >>>> Hallo Hans!
> >>>>
> >>>>> I've started work on this problem yesterday. I discovered that
> >>>>> the MPEG data is placed at the correct memory location so the
> >>>>> shift happens either in the DMA handling (most likely) or in
> >>>>> the internal buffer handling of the driver. I can easily
> >>>>> reproduce it, so that helps a lot. I hope I can find the cause
> >>>>> quickly. I have several ideas, but it needs more debugging and
> >>>>> tracing.
> >>>>
> >>>> Did you find the cause for the bug mentioned above? I don't want
> >>>> to rush, I'm just a bit curious...
> >>>
> >>> I'm slowly closing in on it. It's not as easy to reproduce as I
> >>> thought so
> >>> it is slow going. The bug is probably in the dma_from_device()
> >>> function in
> >>> ivtv-irq.c and is probably related to somehow incorrect handling
> >>> of a DMA
> >>> error. I have to wait for it to happen again before I can be more
> >>> certain.
> >>>
> >>> Hans
> >>
> >> I see this problem on every single recording on my pvr 500.
> >> Please let me know if there is anything I can do to help debug
> >> this since it is so easy for me to reproduce.
> >
> > Can you do the following for me: edit ivtv-irq.c, go to the
> > function dma_from_device(), go to the end of the function and add a
> > IVTV_INFO line just before the 'goto redo_dma;' line:
> >
> > spin_unlock_irqrestore(&itv->DMA_slock, flags);
> > if (redo_dma < 3) {
> > redo_dma++;
> > IVTV_INFO("redma %lx\n", redo_dma);
> > goto redo_dma;
> > }
> > IVTV_DEBUG_WARN(
> > "ENC: REDO DMA took too many tries.\n");
> > ret = -ENOMEM;
> > }
> >
> > return ret;
> > }
> >
> > Whenever things go wrong I always see a 'redma' line in the log. So
> > it is clearly related to a DMA error that the firmware does not
> > correctly recover from. Do you see the same message?
> >
> > Hans
>
> SOrry for the long delay in a response, I was out of town. I tried
> inserting the line as you described, unfortunately, I get a kernel
> oops when I set ivtv_debug=3 with or without the modification. I am
> using 0.4.0 release. Below is the log of the oops. Please let me
> know what else I can do to help.
Don't use the ivtv_debug option or switch to the 0.4.1 dev. snapshot.
This is a known bug that's fixed in 0.4.1.
Hans
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