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Date: Mon, 28 Feb 2011 16:21:57 -0800
From: "Ira W. Snyder" <iws@ovro.caltech.edu>
To: Felix Radensky <felix@embedded-sol.com>
Subject: Re: [PATCH 0/8] fsldma: lockup fixes
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On Mon, Feb 28, 2011 at 11:27:40PM +0200, Felix Radensky wrote:
> Hi Ira,
> 
> On 02/28/2011 11:11 PM, Ira W. Snyder wrote:
> > On Mon, Feb 28, 2011 at 10:15:49PM +0200, Felix Radensky wrote:
> >> Hi Ira,
> >>
> >>> Thank you very much Felix. The dmesg output shows that the controller
> >>> never got an interrupt for the second transaction. The patch below has
> >>> extra debugging information that may help determine why this happens.
> >>> Please apply it and re-run the test.
> >>>
> >>> The last section of dmesg (after "Freeing unused kernel memory") is all
> >>> I need.
> >>>
> >> Attached relevant dmesg portion.
> >>
> > Ok, try this patch on top of the last one.
> >
> > It looks like you used the dmatest module in multi-channel mode last
> > time. One channel makes it easier to debug:
> >
> > modprobe dmatest max_channels=1 threads_per_chan=2 iterations=1
> >
> > Thanks for your help in debugging this. Hopefully this is the last
> > patch to test. :)
> >
> > Ira
> >
> 
> Looks like this was not the last one. The test still fails, see below
> 

>>From this log, it looks like the DMA controller is not generating an
interrupt after the second chain is started. The first chain is finished
before the second thread runs and starts its chain.

The end-of-segments interrupt is completely missing. The part is not
behaving as the datasheet explains it should. Are you sure you applied
the patch and rebuilt the kernel? (Just checking to be sure. I'm very
appreciative of the amount of help you've given me debugging this!)

Can you run this for me:

modprobe dmatest max_channels=1 threads_per_chan=1 iterations=4

Thanks again,
Ira