Subject: Re: aha0: DMA beyond end of ISA
To: Trevin Beattie <>
From: Michael L. VanLoon -- <>
List: current-users
Date: 11/09/1996 00:34:25
>I'm sure this subject has been covered before, but I ignored it because I
>only has 16MB RAM.  Now that I've upgraded to 32MB, this error is halting
>processes at random and it's getting extremely annoying.  Isn't the
>bounce-buffer strategy in isadma.c (or something like that) supposed to
>prevent this problem?

The code in isadma.c is for the motherboard DMA controllers.  It does
not have anything to do with bus-master controllers.

I don't mean to sound harsh, but have you been living in a cave?  This
has only been beat to death on the NetBSD lists over the last two
months or so (and is beat in such a fashion about every six months or
so).  And it's well-documented in many different places.

>If it's not enabled by default, how do I configure
>it?  If there is no fix, can I at least restrict netbsd to using just 16MB
>RAM (without physically taking the additional memory out)?

If this is 1.2, put "options EXTMEM_SIZE=15*1024" (I believe this is
in KiloBytes, correct?) in your kernel config file and build a new
kernel.  This will limit you to 640K base mem + 15MB extended mem.

  Michael L. VanLoon                 
        --<  Free your mind and your machine -- NetBSD free un*x  >--
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