Subject: Re: [PATCH 0/8] fsldma: lockup fixes

From: Felix Radensky <[email-masked]>
Date: Tue, 01 Mar 2011 07:52:39 +0200

Hi Ira,

On 03/01/2011 02:21 AM, Ira W. Snyder wrote:
> 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

Without your patches applied the output of the test above looks
like this:

__dma_request_channel: success (dma0chan0)
dmatest: Started 1 threads using dma0chan0
of:fsl-elo-dma ffe0c300.dma: irq: channel 0, stat = 0xa
of:fsl-elo-dma ffe0c300.dma: irq: End-of-segments INT
of:fsl-elo-dma ffe0c300.dma: irq: clndar 0x2f34d000, nlndar 0x100000000
of:fsl-elo-dma ffe0c300.dma: irq: End-of-link INT
of:fsl-elo-dma ffe0c300.dma: no pending LDs
of:fsl-elo-dma ffe0c300.dma: irq: Exit
of:fsl-elo-dma ffe0c300.dma: chan completed_cookie = 1
of:fsl-elo-dma ffe0c300.dma: LD ef34d000 callback
of:fsl-elo-dma ffe0c300.dma: chan completed_cookie = 1
dma0chan0-copy0: verifying source buffer...
dma0chan0-copy0: verifying dest buffer...
dma0chan0-copy0: #0: No errors with src_off=0xb90 dst_off=0x101c 
len=0x2aea
of:fsl-elo-dma ffe0c300.dma: irq: channel 0, stat = 0xa
of:fsl-elo-dma ffe0c300.dma: irq: End-of-segments INT
of:fsl-elo-dma ffe0c300.dma: irq: clndar 0x2f34d000, nlndar 0x100000000
of:fsl-elo-dma ffe0c300.dma: irq: End-of-link INT
of:fsl-elo-dma ffe0c300.dma: no pending LDs
of:fsl-elo-dma ffe0c300.dma: irq: Exit
of:fsl-elo-dma ffe0c300.dma: chan completed_cookie = 2
of:fsl-elo-dma ffe0c300.dma: LD ef34d000 callback
of:fsl-elo-dma ffe0c300.dma: chan completed_cookie = 2
dma0chan0-copy0: verifying source buffer...
dma0chan0-copy0: verifying dest buffer...
dma0chan0-copy0: #1: No errors with src_off=0x74a dst_off=0x54d len=0x35f5
of:fsl-elo-dma ffe0c300.dma: irq: channel 0, stat = 0xa
of:fsl-elo-dma ffe0c300.dma: irq: End-of-segments INT
of:fsl-elo-dma ffe0c300.dma: irq: clndar 0x2f34d000, nlndar 0x100000000
of:fsl-elo-dma ffe0c300.dma: irq: End-of-link INT
of:fsl-elo-dma ffe0c300.dma: no pending LDs
of:fsl-elo-dma ffe0c300.dma: irq: Exit
of:fsl-elo-dma ffe0c300.dma: chan completed_cookie = 3
of:fsl-elo-dma ffe0c300.dma: LD ef34d000 callback
of:fsl-elo-dma ffe0c300.dma: chan completed_cookie = 3
dma0chan0-copy0: verifying source buffer...
dma0chan0-copy0: verifying dest buffer...
dma0chan0-copy0: #2: No errors with src_off=0x2ad dst_off=0x557 len=0x35e1
of:fsl-elo-dma ffe0c300.dma: irq: channel 0, stat = 0xa
of:fsl-elo-dma ffe0c300.dma: irq: End-of-segments INT
of:fsl-elo-dma ffe0c300.dma: irq: clndar 0x2f34d000, nlndar 0x100000000
of:fsl-elo-dma ffe0c300.dma: irq: End-of-link INT
of:fsl-elo-dma ffe0c300.dma: no pending LDs
of:fsl-elo-dma ffe0c300.dma: irq: Exit
of:fsl-elo-dma ffe0c300.dma: chan completed_cookie = 4
of:fsl-elo-dma ffe0c300.dma: LD ef34d000 callback
of:fsl-elo-dma ffe0c300.dma: chan completed_cookie = 4
dma0chan0-copy0: verifying source buffer...
dma0chan0-copy0: verifying dest buffer...
dma0chan0-copy0: #3: No errors with src_off=0x0 dst_off=0x0 len=0x4000
dma0chan0-copy0: terminating after 4 tests, 0 failures (status 0)

Felix.