From: Lars-Peter Clausen <lars@metafoo.de>
To: Mark Brown <broonie@kernel.org>
Cc: Mike Looijmans <mike.looijmans@topic.nl>,
Joel Fernandes <joelf@ti.com>,
alsa-devel@alsa-project.org
Subject: Re: Query on Audio DMA using DMAEngine
Date: Wed, 03 Jul 2013 11:09:22 +0200 [thread overview]
Message-ID: <51D3EA42.3040205@metafoo.de> (raw)
In-Reply-To: <20130702121345.GL27646@sirena.org.uk>
On 07/02/2013 02:13 PM, Mark Brown wrote:
> On Tue, Jul 02, 2013 at 07:50:16AM +0200, Mike Looijmans wrote:
>> On 07/02/2013 05:33 AM, Joel Fernandes wrote:
[...]
>> This meant I had to use a DMA PARAM slot for every "period". The
>> OMAP L138 has 128 of those slots, so it's no problem to use a bunch
>> of them. Because the chain is cyclic, there is no need to update any
>> DMA parameter while running. All that ALSA needs to do is empty the
>> buffer before the cycle completes and the current position gets
>> overwritten.
>
> This sort of cyclic thing tends to be best, ideally you don't need
> interrupts at all (other than a timer).
Yes, this is usually how it is done. But I'm wondering maybe the EDMA
controller only has a small total amount of slots available.
- Lars
next prev parent reply other threads:[~2013-07-03 9:08 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <083BC63EECB6FD41B8E81CF7FD87CC0F2E4F1488@DLEE08.ent.ti.com>
2013-06-30 12:06 ` Query on Audio DMA using DMAEngine Lars-Peter Clausen
2013-07-01 6:10 ` Mike Looijmans
2013-07-02 1:28 ` Joel Fernandes
2013-07-02 6:02 ` Mike Looijmans
2013-07-02 12:16 ` Mark Brown
2013-07-02 13:30 ` Mike Looijmans
2013-07-02 14:58 ` Mark Brown
2013-07-04 11:00 ` Clemens Ladisch
2013-07-02 3:33 ` Joel Fernandes
2013-07-02 5:50 ` Mike Looijmans
2013-07-02 12:13 ` Mark Brown
2013-07-02 13:40 ` Mike Looijmans
2013-07-03 9:09 ` Lars-Peter Clausen [this message]
2013-07-03 9:43 ` Mark Brown
2013-07-03 13:17 ` Mike Looijmans
[not found] ` <51D4245F.8070307-Oq418RWZeHk@public.gmane.org>
2013-07-03 19:56 ` Joel Fernandes
[not found] ` <20130703094307.GE27646-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
2013-07-03 17:55 ` [alsa-devel] " Joel Fernandes
[not found] ` <51D46598.6070005-l0cyMroinI0@public.gmane.org>
2013-07-03 18:12 ` Mark Brown
2013-07-04 5:56 ` Mike Looijmans
2013-07-04 10:49 ` Mark Brown
2013-07-03 18:18 ` [alsa-devel] " Joel Fernandes
2013-07-04 6:06 ` Mike Looijmans
2013-07-04 10:53 ` Mark Brown
[not found] ` <51D510EA.1030809-Oq418RWZeHk@public.gmane.org>
2013-07-04 10:59 ` [alsa-devel] " Sekhar Nori
2013-08-14 4:30 ` Joel Fernandes
2013-08-14 4:53 ` Joel Fernandes
2013-08-14 14:10 ` Mike Looijmans
2013-08-14 12:06 ` Mark Brown
2013-07-02 1:04 ` Joel Fernandes
2013-07-03 9:07 ` Lars-Peter Clausen
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