Messages in this thread | | | Date | Tue, 1 Dec 2015 14:58:35 +0200 | Subject | Re: [RFC v02 01/15] dmaengine: core: Allow NULL mask pointer in __dma_device_satisfies_mask() | From | Andy Shevchenko <> |
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On Tue, Dec 1, 2015 at 11:47 AM, Peter Ujfalusi <peter.ujfalusi@ti.com> wrote: > On 11/30/2015 04:35 PM, Andy Shevchenko wrote: >> On Mon, Nov 30, 2015 at 3:45 PM, Peter Ujfalusi <peter.ujfalusi@ti.com> wrote: >>> Treat as true condition the case when the mask is NULL. >> >> What do you think about setting some default (all "on") mask when mask >> is not supplied? > > Probably rephrasing the commit message to say that when the mask is NULL it > means that the caller does not care about the capabilities of the dma device > thus return with true in such a case. > > We could also drop this patch and in private_candidate() : > > - if (!__dma_device_satisfies_mask(dev, mask)) { > + if (mask && !__dma_device_satisfies_mask(dev, mask)) { > pr_debug("%s: wrong capabilities\n", __func__); > return NULL; > }
Between patch and above proposal I would choose the latter one.
>> I don't know for sure but there might be cases when you don't want >> literally *any* channel to satisfy. > > Or set DMA_SLAVE only in dma_request_chan()? What happens if we have cases > when we are able to request channel for memcpy via dma_request_chan() > (dedicated memcpy channel/DMA engine?) in that case we will have the SLAVE > set, but not MEMCPY, or any other variation we do not know yet?
Frankly, have no idea.
-- With Best Regards, Andy Shevchenko
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