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From: "Joachim Förster" <mls.JOFT@gmx.de>
To: alsa-devel@alsa-project.org
Subject: ALSA always writes _whole_ periods, right?
Date: Wed, 13 Jun 2007 18:23:38 +0200	[thread overview]
Message-ID: <1181751818.5752.13.camel@localhost> (raw)


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Hi ALSA devs,

I have a quick question regarding the filling of the usual ring buffer
in RAM (used by sound controllers via DMA), just to be really sure:

Is it true, that ALSA always writes (via mmap'ing) _whole_ periods?

I took snd-dummy and modified it to use "ack()" method and tried to
confirm, if the above is true _without_ memory mapping (classical
read/write). It seem's to be true, ALSA is "filling up" the last (not
always complete) period - e.g. if the played wav file is not a multiple
of periodsize in length.
But well, with mmap, I cannot see the copying action (done by ALSA
library, right?) ... so, thus my question ;-) .

Thanks,
 Joachim


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             reply	other threads:[~2007-06-13 16:23 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-06-13 16:23 Joachim Förster [this message]
2007-06-14 10:39 ` ALSA always writes _whole_ periods, right? Takashi Iwai
2007-06-16 21:35   ` Joachim Förster
2007-06-20 10:45     ` Takashi Iwai
     [not found]       ` <1182677696.5697.25.camel@localhost>
2007-06-27 12:47         ` Takashi Iwai

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