From mboxrd@z Thu Jan 1 00:00:00 1970 From: vinod.koul@intel.com (Vinod Koul) Date: Thu, 8 Dec 2016 21:10:18 +0530 Subject: Tearing down DMA transfer setup after DMA client has finished In-Reply-To: References: <20161125045549.GC2698@localhost> <092f44ee-4560-be17-25f7-00948dba3cfa@free.fr> <20fc9020-7278-bc2f-2a8d-43aff5cabff8@free.fr> <20161206051222.GQ6408@localhost> <5846B237.8060409@free.fr> <20161207164341.GX6408@localhost> <20161208103921.GC6408@localhost> Message-ID: <20161208154018.GD6408@localhost> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Dec 08, 2016 at 11:44:53AM +0000, M?ns Rullg?rd wrote: > Vinod Koul writes: > > > On Wed, Dec 07, 2016 at 04:45:58PM +0000, M?ns Rullg?rd wrote: > >> Vinod Koul writes: > >> > >> > On Tue, Dec 06, 2016 at 01:14:20PM +0000, M?ns Rullg?rd 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." That only tells me you haven't looked enough and want to rant! FWIW look at ALSA-dmaengine lib, thereby every audio driver that uses it. I could find other examples and go on and on, but that's besides the point and looks like you don't want to listen to people telling you something.. -- ~Vinod