Re: [PATCH 1/2] dma: cppi41: start tear down only if channel is busy

[George Cherian]

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@xxxxxx>
> > ---
> >   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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