Messages in this thread |  | | Subject | Re: [PATCH v2 03/15] dmaengine: Add no_wakeup parameter to dmaengine_prep_dma_cyclic() | From | Vinod Koul <> | Date | Fri, 14 Sep 2012 08:57:59 +0530 |
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On Thu, 2012-09-13 at 16:38 +0100, Russell King - ARM Linux wrote: > On Thu, Sep 13, 2012 at 05:27:09PM +0200, Lars-Peter Clausen wrote: > > Hm... Do you think it would work as well if we implement this by setting the > > callback for the descriptor to NULL? If the callback is NULL there is > > nothing to at the end of a transfer/period and the dma engine driver may > > choose to disable interrupts. This would also benefit non cyclic transfers > > where the callback is NULL and we do not need add the new parameter to > > dmaengine_prep_dma_cyclic. > > Actually, there's a way to do that already. DMA_PREP_INTERRUPT. > Unfortunately, most DMA engine slave API users don't set it when they > setup their transfer: > > * @DMA_PREP_INTERRUPT - trigger an interrupt (callback) upon completion of > * this transaction Looks like I have repeated the correct action! > > if we fixed that, then we could use the lack of it to avoid the interrupt. > > However, cyclic transfers don't have the flags parameter used to pass this > bit. Yet another bit of yucky inconsistent design in DMA engine land... > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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