Subject: Re: DMA beyond end of ISA with other scsi cards?
To: Scott Reynolds <scottr@Plexus.COM>
From: Justin T. Gibbs <>
List: port-i386
Date: 11/13/1996 14:51:05
>On Tue, 12 Nov 1996, Justin T. Gibbs wrote:
>> Well considering Leonard's sources, I doubt that he is wrong.  Here is
>> what the Linux Buslogic driver has to say about this:
>>   /*
>>     BusLogic BT-445S Host Adapters prior to board revision E have a
>>     hardware bug whereby when the BIOS is enabled, transfers to/from the
>>     same address range the BIOS occupies modulo 16MB are handled
>>     incorrectly.  Only properly functioning BT-445S boards have firmware
>>     version 3.37, so we require that ISA Bounce Buffers be used for the
>>     buggy BT-445S models if there is more than 16MB memory.      
>>   */
>My board has firmware version 3.37; does the comment above mean that this
>is why I'm not having any problems?  It isn't clear to me exactly what the
>above means, at any rate. :-)

It means that any time you transfer to memory in the range of
(X * 16MB) + BIOS offset to (X * 16MB) + BIOS offset + BIOS size, you lose.

It appears that 3.37 is okay.
Justin T. Gibbs
  FreeBSD: Turning PCs into workstations