On Fri, Dec 14, 2012 at 1:34 AM, Andrew Morton
<a...@linux-foundation.org> wrote:
> On Mon, 10 Dec 2012 13:37:44 +0200
> Andy Shevchenko <andriy.shevche...@linux.intel.com> wrote:
>
>> We get a warning if CONFIG_DMA_API_DEBUG=y
>>
>> [ 28.150631] WARNING: at lib/dma-debug.c:933 check_unmap+0x5d6/0x6ac()
>> [ 28.157058] dw_dmac dw_dmac.0: DMA-API: device driver failed to check map
>> error[device address=0x0000000035698305] [size=14365 bytes] [mapped as
>> single]
>> --- a/drivers/dma/dmatest.c
>> +++ b/drivers/dma/dmatest.c
>> @@ -378,15 +378,35 @@ static int dmatest_func(void *data)
>>
>> dma_srcs[i] = dma_map_single(dev->dev, buf, len,
>> DMA_TO_DEVICE);
>> + ret = dma_mapping_error(dev->dev, dma_srcs[i]);
>> + if (ret) {
>> + unmap_src(dev->dev, dma_srcs, len, i);
>> + pr_warn("%s: #%u: mapping error %d with "
>> + "src_off=0x%x len=0x%x\n",
>> + thread_name, total_tests - 1, ret,
>> + src_off, len);
>> + failed_tests++;
>> + continue;
>> + }
>
> The changelog and the code don't match. Which one is out of date?
I'm afraid I didn't get what is wrong.
dmatest maps memory via dma_map_single() call. And it asks dmaengine
(at the end the DMA controller driver) to unmap them after usage.
Exactly at that time user gets a warning. And this warning is
independent of DMA controller in use.
--
With Best Regards,
Andy Shevchenko
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