From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>,
Mark Brown <broonie@opensource.wolfsonmicro.com>,
Liam Girdwood <lrg@ti.com>, Tony Lindgren <tony@atomide.com>,
Vinod Koul <vinod.koul@intel.com>, Dan Williams <djbw@fb.com>,
Jarkko Nikula <jarkko.nikula@bitmer.com>,
alsa-devel@alsa-project.org, linux-omap@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>,
Ricardo Neri <ricardo.neri@ti.com>
Subject: Re: [PATCH v2 03/15] dmaengine: Add no_wakeup parameter to dmaengine_prep_dma_cyclic()
Date: Thu, 13 Sep 2012 16:38:24 +0100 [thread overview]
Message-ID: <20120913153824.GK28448@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <5051FB4D.3000009@metafoo.de>
On Thu, Sep 13, 2012 at 05:27:09PM +0200, Lars-Peter Clausen wrote:
> Hm... Do you think it would work as well if we implement this by setting the
> callback for the descriptor to NULL? If the callback is NULL there is
> nothing to at the end of a transfer/period and the dma engine driver may
> choose to disable interrupts. This would also benefit non cyclic transfers
> where the callback is NULL and we do not need add the new parameter to
> dmaengine_prep_dma_cyclic.
Actually, there's a way to do that already. DMA_PREP_INTERRUPT.
Unfortunately, most DMA engine slave API users don't set it when they
setup their transfer:
* @DMA_PREP_INTERRUPT - trigger an interrupt (callback) upon completion of
* this transaction
if we fixed that, then we could use the lack of it to avoid the interrupt.
However, cyclic transfers don't have the flags parameter used to pass this
bit. Yet another bit of yucky inconsistent design in DMA engine land...
next prev parent reply other threads:[~2012-09-13 15:39 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-13 13:37 [PATCH v2 00/15] ASoC: OMAP: Convert to use dmaengine Peter Ujfalusi
2012-09-13 13:37 ` [PATCH v2 01/15] dmaengine: omap: Support for element mode in cyclic DMA Peter Ujfalusi
2012-09-13 13:37 ` [PATCH v2 02/15] dmaengine: omap: Add support for pause/resume in cyclic dma mode Peter Ujfalusi
2012-09-13 13:37 ` [PATCH v2 03/15] dmaengine: Add no_wakeup parameter to dmaengine_prep_dma_cyclic() Peter Ujfalusi
2012-09-13 15:27 ` Lars-Peter Clausen
2012-09-13 15:38 ` Russell King - ARM Linux [this message]
2012-09-14 3:27 ` Vinod Koul
2012-09-14 7:15 ` Peter Ujfalusi
2012-09-14 3:26 ` Vinod Koul
2012-09-14 7:18 ` [alsa-devel] " Peter Ujfalusi
2012-09-14 8:13 ` Lars-Peter Clausen
2012-09-14 8:50 ` Vinod Koul
2012-09-14 9:28 ` Peter Ujfalusi
2012-09-14 9:38 ` Vinod Koul
2012-09-14 10:01 ` Russell King - ARM Linux
2012-09-14 7:12 ` Peter Ujfalusi
2012-09-13 13:37 ` [PATCH v2 04/15] dmaengine: Pass no_wakeup parameter via device_prep_dma_cyclic() callback Peter Ujfalusi
2012-09-14 3:24 ` Vinod Koul
2012-09-14 7:07 ` Peter Ujfalusi
2012-09-17 6:34 ` Shawn Guo
2012-09-17 7:16 ` Peter Ujfalusi
2012-09-17 7:23 ` Shawn Guo
2012-09-17 9:01 ` Linus Walleij
2012-09-18 8:31 ` Russell King - ARM Linux
2012-09-18 9:00 ` Vinod Koul
2012-09-18 12:22 ` Linus Walleij
2012-09-13 13:37 ` [PATCH v2 05/15] dmaengine: omap-dma: Add support for no_wakeup in cyclic mode Peter Ujfalusi
2012-09-13 13:37 ` [PATCH v2 06/15] ASoC: omap-mcbsp: Use sDMA packet mode instead of frame mode Peter Ujfalusi
2012-09-13 13:37 ` [PATCH v2 07/15] ASoC: omap-pcm: Select sDMA synchronization based on packet_size Peter Ujfalusi
2012-09-13 13:37 ` [PATCH v2 08/15] ASoC: OMAP: Remove sync_mode from omap_pcm_dma_data struct Peter Ujfalusi
2012-09-13 13:37 ` [PATCH v2 09/15] ASoC: omap-pcm: Prepare to configure the DMA data_type based on stream properties Peter Ujfalusi
2012-09-13 13:38 ` [PATCH v2 10/15] ARM: OMAP4: hwmod_data: Add resource names to McPDM memory ranges Peter Ujfalusi
2012-09-13 13:38 ` [PATCH v2 11/15] ASoC: omap-mcpdm: Use platform_get_resource_* to get resources Peter Ujfalusi
2012-09-13 13:38 ` [PATCH v2 12/15] ASoC: OMAP: mcbsp, mcpdm, dmic: Let omap-pcm to pick the dma_type Peter Ujfalusi
2012-09-13 13:38 ` [PATCH v2 13/15] ASoC: omap-pcm, omap-dmic: Change the use of omap_pcm_dma_data->data_type Peter Ujfalusi
2012-09-13 13:38 ` [PATCH v2 14/15] ASoC: OMAP: mcbsp, mcpdm, dmic, hdmi: Set dma_data at startup time Peter Ujfalusi
2012-09-13 13:38 ` [PATCH v2 15/15] ASoC: omap-pcm: Convert to use dmaengine Peter Ujfalusi
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