[alsa-devel] [RFC][PATCH 2/3] ASoC: OMAP: Make use of DMA channel self linking on OMAP1510

Jarkko Nikula jhnikula at gmail.com
Mon Aug 17 11:18:58 CEST 2009

On Mon, 10 Aug 2009 10:50:04 +0200
Janusz Krzysztofik <jkrzyszt at tis.icnet.pl> wrote:

> Use newly implemented DMA channel self linking on OMAP1510 like on other OMAP
> models. Remove unnecessary DMA transfer restart from interrupt handler
> routine.
> The interrupt routine used to maintain a period index, originally needed for
> counting up periods up to a full buffer in order to restart the DMA transfer.
> For some time, this counter is also used as a replacement for hardware DMA
> progress counter that has been found unusable on OMAP1510 in case of playback.
> Thus, the period index calculation cannot be omitted completely. However, the
> accuracy of this counter can still suffer from missing DMA interrupts.
> In order to work correctly, it requires patch 1 from this series also applied:
> [RFC][PATCH 1/3] ARM: OMAP: DMA: Add support for DMA channel self linking on OMAP1510
> Created against linux-2.6.31-rc5.
> Tested on Amstrad Delta.
> Signed-off-by: Janusz Krzysztofik <jkrzyszt at tis.icnet.pl>
Nice to see code to be more uniform across the OMAP's. Note this
depends on patch 1 which touches the arch/arm/plat-omap/dma.c.

Acked-by: Jarkko Nikula <jhnikula at gmail.com>

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