From: "christian pellegrin" <chripell@gmail.com>
To: Mark Brown <broonie@sirena.org.uk>
Cc: David Anders <dave123_aml@yahoo.com>,
alsa-devel@alsa-project.org, Ben Dooks <ben-linux@fluff.org>
Subject: Re: possible problem in s3c24xx-pcm.c in git-devel branch
Date: Thu, 13 Nov 2008 16:40:03 +0100 [thread overview]
Message-ID: <cabda6420811130740u325cf60bse8401af768fb7340@mail.gmail.com> (raw)
In-Reply-To: <20081113151701.GG31592@sirena.org.uk>
On Thu, Nov 13, 2008 at 4:17 PM, Mark Brown <broonie@sirena.org.uk> wrote:
> On Thu, Nov 13, 2008 at 03:57:08PM +0100, christian pellegrin wrote:
>
>>
>> but this really could be "playing with DMA" since I'm not sure why
>> there is a 1 (since min_period is 2 I would guess 2 is the right
>> value). Anyway with this change play and capture work well.
>
> See the commit log - the underlying DMA code restricts the number of
> buffers that can be queued up prior to the start of DMA.
>
>>
AFAIK it's limited to 2 transfers, one loaded and one running. It
could beneficial to have more of them (so the DMA doesn't stop if one
interrupt is delayed for too much time). But I don't know if it's so
critical. A period (4k) with cd quality sound takes 23 ms to be
played. An embedded system not responding to irqs for all this time
probably has worse issues.
--
Christian Pellegrin, see http://www.evolware.org/chri/
"Real Programmers don't play tennis, or any other sport which requires
you to change clothes. Mountain climbing is OK, and Real Programmers
wear their climbing boots to work in case a mountain should suddenly
spring up in the middle of the computer room."
next prev parent reply other threads:[~2008-11-13 15:40 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-13 14:57 possible problem in s3c24xx-pcm.c in git-devel branch christian pellegrin
2008-11-13 15:17 ` Mark Brown
2008-11-13 15:40 ` christian pellegrin [this message]
2008-11-13 16:09 ` Mark Brown
2008-11-14 12:46 ` Mark Brown
2008-11-14 16:20 ` christian pellegrin
2008-11-17 11:00 ` Mark Brown
2008-11-13 15:44 ` David Anders
2008-11-13 16:02 ` christian pellegrin
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