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From: "John S. Dyson" <toor@dyson.iquest.net>
Message-Id: <199704011752.MAA02576@dyson.iquest.net>
Subject: Re: Bounce Buffers
In-Reply-To: <Pine.BSF.3.91.970401085538.1730Z-100000@dyslexic.phoenix.net> from Geoff Mohler at "Apr 1, 97 08:58:08 am"
To: gemohler@c-com.net (Geoff Mohler)
Date: Tue, 1 Apr 1997 12:52:51 -0500 (EST)
Cc: current@freebsd.org
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> I was getting this on a stock 2.2.1 installation:
> 
> Panic: Bounce Buffers Out Of Range
> =-=-=-=-=-
> 
> I got this when I took the GENERIC *or any* Kernel definition file, and 
> added the line:
> 		options		"MAXMEM=262144"
> 
> Then it would report the above error on bootup, just after reporting 
> kernel bus options.
> 
> Now, the problem only went away after removing a megabyte of ram.  When I 
> changed it to:
> 		options		"MAXMEM=261120"
> 
> ..it works fine.
> 
You can also remove the bounce-buffers define.  Those aren't usually needed
with new technology hardware.

The problem is that the kernel takes so much space, that there isn't room
<16MB for bounce buffers.  Unless we get lots of users with > 128M using
ISA SCSI adaptors, I don't think that it is worth fixing the memory
allocation code, until we create physical memory type attributes.

John