Subject: Re: Before and after the 1.1 release
To: Charles Hannum <>
From: Michael L. VanLoon -- <>
List: current-users
Date: 10/06/1995 19:04:23
>* Bounce buffers.  All of the other bus-mastering drivers need to be
>updated.  Note also that on EISA machines, we don't need to bounce in
>many cases, because there's an extra register for the upper 8 bits of
>the DMA address.  (I haven't had time to look at the PR, so this may
>have been addressed already.)

I would put it more strongly: *DON'T* bounce-buffer my EISA machine --
I don't want to waste the CPU cycles and memory on it since my EISA
bus accesses that memory nicely by itself.

I realize there are some broken EISA motherboards out there that don't
support full 32-bit addresses.  These boards are the special case.  I
don't know if there's any coherent probe which can detect these, so
bounce buffers can be turned on as needed.  The ugly hack might be to
just disable bounce buffers on EISA unless a "secret" option is turned
on in the kernel config.

The point being: please don't break working EISA drivers with bounce

  Michael L. VanLoon                       
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