Re: bootblock and -I

["Michael L. Hitch" <mhitch%msu.oscs.montana.edu@localhost>]

Allen Wittenauer <allenw%iobm.com@localhost> writes: 
> > On Wed, Oct 21, 1998 at 10:57:12AM -0700, Allen Wittenauer wrote:
> > > 
> > > Is it just me, or does the -I parameter not work in NetBSD 1.3.2 
> > > w/bootblock 
> > > v2.0.  It *does* work from LoadBSD v2.14 using the same kernel, however.  
> > > Is 
> > > there any way just force the kernel to not do synchronous xfers at all?  
> > 
> > 
> > The code to handle it is there. I guess you have a slightly different 
> > problem. Can you send me the kernel startup messages, please, which releate
> > to the scsi?
> 
> Sure.  When it boots from loadbsd-2.14 [-I ff -a -S netbsd], SCSI looks like 
> so:
...
> With netbsd -I ff -a -S from the bootblocks, I get this:

  The explaination is simple (and probably not documented anywhere):

        loadbsd expects the value for 'I' to be hexadecimal.

        bootblock expects the value to be a C-style number.

  So with the bootblock loader, you need to do "I 0xff".

  Also, another way to force the kernel to disable sync negotiation by
default would be to modify the variable that the "I" option sets.  This
can be done by modifying the driver source, or using binpatch.  The
variable to be modified is the byte array 'sbic_inhibit_sync', where
each byte corresponds to a SCSI target.  The binpatch commands for this
would be something like:

        binpatch -s _sbic_inhibit_sync -r 0x01010101 netbsd
        binpatch -s _sbic_inhibit_sync -o 4 -r 0x01010101 netbsd

[presuming I still remember how to run binpatch :-) ]

Michael
---
Michael L. Hitch                        mhitch%montana.edu@localhost
Computer Consultant,  Information Technology Center
Montana State University, Bozeman, MT     USA