From: Lee Revell <rlrevell@joe-job.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Takashi Iwai <tiwai@suse.de>,
Linux Kernel list <linux-kernel@vger.kernel.org>
Subject: Re: Mac mini sound woes
Date: Mon, 28 Mar 2005 22:36:09 -0500 [thread overview]
Message-ID: <1112067369.19014.24.camel@mindpipe> (raw)
In-Reply-To: <1111966920.5409.27.camel@gaston>
On Mon, 2005-03-28 at 09:42 +1000, Benjamin Herrenschmidt wrote:
> It seems that Apple's driver has an in-kernel framework for doing volume
> control, mixing, and other horrors right in the kernel, in temporary
> buffers, just before they get DMA'ed (gack !)
>
> I want to avoid something like that. How "friendly" would Alsa be to
> drivers that don't have any HW volume control capability ? Does typical
> userland libraries provide software processing volume control ? Do you
> suggest I just don't do any control ? Or should I implement a double
> buffer scheme with software gain as well in the kernel driver ?
alsa-lib handles both mixing (dmix plugin) and volume control (softvol
plugin) in software for codecs like this that don't do it in hardware.
Since Windows does mixing and volume control in the kernel (ugh) it's
increasingly common to find devices that cannot do these. You don't
need to handle it in the driver at all.
dmix has been around for a while but softvol plugin is very new, you
will need ALSA CVS or the upcoming 1.0.9 release.
Lee
next prev parent reply other threads:[~2005-03-29 3:36 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-27 23:42 Mac mini sound woes Benjamin Herrenschmidt
2005-03-28 1:42 ` Andrea Arcangeli
2005-03-28 2:34 ` Benjamin Herrenschmidt
2005-03-29 3:36 ` Lee Revell [this message]
2005-03-29 3:41 ` Benjamin Herrenschmidt
2005-03-29 7:47 ` Marcin Dalecki
2005-03-29 8:18 ` Benjamin Herrenschmidt
2005-03-29 9:22 ` Marcin Dalecki
2005-03-29 10:22 ` Takashi Iwai
2005-03-30 1:45 ` Marcin Dalecki
2005-03-30 2:08 ` Lee Revell
2005-03-30 4:14 ` Lee Revell
2005-03-30 5:15 ` Steven Rostedt
2005-03-29 22:13 ` Lee Revell
2005-03-29 23:25 ` Chris Friesen
2005-03-29 23:39 ` Benjamin Herrenschmidt
2005-03-30 1:48 ` Marcin Dalecki
2005-03-30 5:42 ` Lee Revell
2005-03-30 1:45 ` Marcin Dalecki
2005-03-29 10:02 ` Takashi Iwai
2005-03-29 11:04 ` Benjamin Herrenschmidt
2005-03-29 12:12 ` Takashi Iwai
2005-03-29 19:05 ` Lee Revell
2005-03-29 19:31 ` Takashi Iwai
2005-03-29 20:11 ` Lee Revell
2005-03-29 22:03 ` Benjamin Herrenschmidt
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