Date: Fri, 14 Mar 2008 22:29:32 +0900 (JST)
Message-Id: <20080314.222932.74752532.anemo@mba.ocn.ne.jp>
To: haavard.skinnemoen@atmel.com
Cc: linux-kernel@vger.kernel.org, hcegtvedt@atmel.com, avictor.za@gmail.com,
       tiwai@suse.de
Subject: Re: [PATCH] at73c213: Fix DMA size at the end of DMA buffer
From: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
In-Reply-To: <20080314104445.32f4da40@hskinnemo-gx620.norway.atmel.com>
References: <20080310.234306.15242180.anemo@mba.ocn.ne.jp>
	<20080314104445.32f4da40@hskinnemo-gx620.norway.atmel.com>
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On Fri, 14 Mar 2008 10:44:45 +0100, Haavard Skinnemoen <haavard.skinnemoen@atmel.com> wrote:
> > +		size = runtime->period_size * runtime->channels;
> > +		if (next_period == runtime->periods - 1)
> > +			size += (runtime->buffer_size % runtime->period_size)
> > +				* runtime->channels;
> 
> Ow. That looks expensive. Isn't there any way we can force the client
> to select sane values of buffer_size and period_size?

Well, I suppose it is not _too_ expensive. :)

> It seems like a reasonable demand that buffer_size is a multiple of
> period_size, doesn't it?

But actually it can happen.  And I gave up understanding how are these
parameters determined...  If there were any way the driver can enforce
that constraint, it would be better fix.

Iwai-san, any comments from alsa guru?

---
Atsushi Nemoto
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