On Wed, 2013-05-29 at 13:42 +0200, Lars-Peter Clausen wrote:
Add a capability which allows dmaengine consumers to query whether a dmaengine controller supports the DMA_PAUSE and DMA_RESUME commands. Sometimes a user of the dmaengine API needs to know in advance if a channel will support pause/resume. E.g. in ALSA the information whether it is possible to pause/resume a audio stream or whether it is necessary to abort and restart the stream is communicated to userspace so it can act accordingly.
- This mail-list is not correct for this patch - use get_maintainer.pl, if you dont know but you already know! - always CC maintainers
the enum dma_transaction_type reports what kind of transactions DMA controller is capable of. This is not for capabilities of a given transaction type, so this approach is not right.
Unfortunately, this is not supported by dmaengine atm. We had discussed this in last plumbers, and discussion with Matt was to add capability API (at least for slave usages). The work from Matt had reached a good point but unfortunately didn't reach its conclusion. [1]
Let me resurrect those patches and add the pause, resume query to it in more generic way
-- ~Vinod