Tearing down DMA transfer setup after DMA client has finished

Måns Rullgård mans at mansr.com
Thu Dec 8 03:44:53 PST 2016


Vinod Koul <vinod.koul at intel.com> writes:

> On Wed, Dec 07, 2016 at 04:45:58PM +0000, Måns Rullgård wrote:
>> Vinod Koul <vinod.koul at intel.com> writes:
>> 
>> > On Tue, Dec 06, 2016 at 01:14:20PM +0000, Måns Rullgård wrote:
>> >> 
>> >> That's not going to work very well.  Device drivers typically request
>> >> dma channels in their probe functions or when the device is opened.
>> >> This means that reserving one of the few channels there will inevitably
>> >> make some other device fail to operate.
>> >
>> > No that doesnt make sense at all, you should get a channel only when you
>> > want to use it and not in probe!
>> 
>> Tell that to just about every single driver ever written.
>
> Not really, few do yes which is wrong but not _all_ do that.

Every driver I ever looked at does.  Name one you consider "correct."

-- 
Måns Rullgård



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