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SubjectRe: [PATCH 1/2] dma: cppi41: start tear down only if channel is busy
On 2/27/2014 2:17 PM, Shevchenko, Andriy wrote:
> On Thu, 2014-02-27 at 10:44 +0530, George Cherian wrote:
>> Start the channel tear down only if the channel is busy, else just
>> bail out. In some cases its seen that by the time the tear down is
>> initiated the cppi completes the DMA, especially in ISOCH transfers.
>>
>> Signed-off-by: George Cherian <george.cherian@ti.com>
>> ---
>> drivers/dma/cppi41.c | 7 +++++--
>> 1 file changed, 5 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/dma/cppi41.c b/drivers/dma/cppi41.c
>> index c18aebf..d028f36 100644
>> --- a/drivers/dma/cppi41.c
>> +++ b/drivers/dma/cppi41.c
>> @@ -620,12 +620,15 @@ static int cppi41_stop_chan(struct dma_chan *chan)
>> u32 desc_phys;
>> int ret;
>>
>> + desc_phys = lower_32_bits(c->desc_phys);
>> + desc_num = (desc_phys - cdd->descs_phys) / sizeof(struct cppi41_desc);
>> + if (!cdd->chan_busy[desc_num])
>> + return 0;
>> +
>> ret = cppi41_tear_down_chan(c);
>> if (ret)
>> return ret;
>>
>> - desc_phys = lower_32_bits(c->desc_phys);
>> - desc_num = (desc_phys - cdd->descs_phys) / sizeof(struct cppi41_desc);
>> WARN_ON(!cdd->chan_busy[desc_num]);
> Do you still need this WARN_ON?

Yes in some cases wherein the channel is busy and tear down didn't
happen successfully.
>
>> cdd->chan_busy[desc_num] = NULL;
>>
>


--
-George



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