Subject: Re: vm_fault on i386...
To: Andrew K. Adams <>
From: Jason Thorpe <>
List: current-users
Date: 06/18/1997 11:10:31
On Wed, 18 Jun 1997 10:06:39 -0400 
 "Andrew K. Adams" <> wrote:

 > root@wraith# vm_fault(0xf880d100,0,1,0) -> 5
 > kernal: page fault trap, code = 0
 > stopped at _pmap_changebit + 0x83: movl 0(%edx),%eax
 > db>
 > My PC is a 386 w/16MB of RAM, Adaptec ISA SCSI controller, SMC ISA
 > 10Mb NIC -- I use com0 for console (and I believe the "old" boot code)
 > and com1 for PPP dialup, which is running most of the time.  My 1.2C
 > kernel had BIOSEXTMEM=14964 set.  I have tried both setting and
 > un-setting this option in the 1.2G kernel (since I was unsure if the
 > new bounce buffer support was "auto-magic").
 > Any help would be appreciated.

You deref'd a NULL pointer... I need a traceback before I can help you
with this.

The bounce buffer code is automagic... however, if you only have 16M in
your system, it's not supposed to use bounce buffers at all, since direct
ISA DMA will work.

Jason R. Thorpe                             
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