On Wed, 2012-02-01 at 12:58 +0100, Guennadi Liakhovetski wrote: > > The two things are completely orthogonal and shouldn't be clubbed. > > For your issue we need a separate debate on how to solve this... I am > > open to ideas... > > Well, I'm not sure whether they are necessarily always orthogonal, they > don't seem so in my case at least. We definitely can use our approach - > configure the channel during allocation. I _think_ we could also perform > the configuration on a per-transfer basis, during the prepare stage, as > this RFC is suggesting, but that definitely would require reworking the > driver somewhat and changing the concept. The current concept is a fixed > DMA channel allocation to slaves for as long as the slave is using DMA. > This is simpler, avoids some overhead during operation and fits well with > the dmaengine PRIVATE channel concept. So, given the choice, we would > prefer to perform the configuration during channel allocation. > > Maybe there are cases, where the driver absolutely needs this additional > information during allocation, in which case my proposal would be the only > way to go for them. what are you trying to address, sending controller specific information at allocation or the channel allocation itself. I kind of sense both. But apprach here is discussed is to pass paramters which are required for each transfer, not static for a channel, hence the additional controller specific parameter in respective prepare. > > I'll post an RFC soon - stay tuned:-) Patch is always the best idea :-)
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