From mboxrd@z Thu Jan 1 00:00:00 1970 From: broonie@opensource.wolfsonmicro.com (Mark Brown) Date: Thu, 10 May 2012 10:42:06 +0100 Subject: Cyclic DMA - callback properties and tx_status residue In-Reply-To: <1336621458.1540.280.camel@vkoul-udesk3> References: <20120502144555.GA4456@n2100.arm.linux.org.uk> <1335974475.1593.20.camel@vkoul-udesk3> <20120502162702.GE3548@n2100.arm.linux.org.uk> <20120509093334.GS26481@n2100.arm.linux.org.uk> <20120509111614.GH3955@opensource.wolfsonmicro.com> <20120509121945.GT26481@n2100.arm.linux.org.uk> <1336621458.1540.280.camel@vkoul-udesk3> Message-ID: <20120510094205.GM3908@opensource.wolfsonmicro.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, May 10, 2012 at 09:14:18AM +0530, Vinod Koul wrote: > For audio needs I think it is fine if we miss, as long as subsequent > comes untill we get underrun/overrun. No, - this is what Russell has been reporting. Due to the lack of position callbacks the ASoC dmaengine stuff is counting completions to work out where it is in the buffer. If we miss completions then the drivers will start to loose track of where they are in the buffer. If we had usable position reporting this would work OK, or if the ASoC code were changed to remember where each buffer ends and get that information passed back in the completion argument then it could recover that way (but that's fairly painful). -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 836 bytes Desc: Digital signature URL: