Subject: Re: [ecasound] ecasound/alsa-ice1712 won't work with 384MB RAM!
From: Kai Vehmanen (k@eca.cx)
Date: Sun Feb 25 2001 - 16:26:52 EET
On Fri, 23 Feb 2001, J. Gareth Williams wrote:
> it turns out it had nothing to do with debian - not suprisingly - but the
> truth turned out to be even more bizarre. I had 384MB of RAM in my box and
> it would not work. Take out a 128MB module, and ta-da - it works. I
> repeated it several times.
[...]
> does that make any sense at all?
In a way it does. Highend audio cards like the Delta66 require huge
blocks of physical memory to do their DMA-transfers. Here's a quote
from Paul Davis... (from linux-audio-dev):
--cut--
As has been discussed on alsa-devel several times over the last year,
you need to ensure that the snd-rme9652_mem module is loaded *early*
in the boot sequence.
its an absolute h/w requirement that this card needs 1.7MB of
physically contiguous RAM to work. the way the Linux VM system works,
its very hard to get that kind of memory on many systems (with < 512MB
of RAM) once fsck and other startup programs have executed.
i modified my rc files to ensure that this happened.
the only other solutions involve even uglier kernel hacks. FWIW,
Windows and the MacOS both suffer from the same problem.
--cut--
... so it's a very real problem. I don't know how this issue is handled by
the Delta66 driver. Some of these soundcards support scatter&gather, so
the DMA-memory block doesn't have to be contiguous. It might be that
Delta66 can't handle DMA-regions above 128MB, etc, etc .. but you should
ask about this on alsa-devel (or mailing directly to Delta66 driver
author).
> i'm not sure if it's ecasound or alsa... anyone else know of another
> multitrack-capable player/recorder i could try to see where the problem
I'm pretty sure this has nothing to do with ecasound. In Linux, normal
apps have very little to do with hardware issues (and this a good thing
:)). So it's probably a kernel problem, either in Linux itself, or in the
ALSA driver modules.
BTW; You can specify the physical memory size as a kernel boot
parameter (for instance using LILO -> /etc/lilo.conf), so
you can play with different memory sizes without having
to physically add nor remove memory modules.
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