Re: constraints on rbus_min_start?

[Bernd Ernesti <netbsd%lists.veego.de@localhost>]

On Fri, Jan 11, 2008 at 09:26:52PM +0000, Steven M. Bellovin wrote:
> On Tue, 8 Jan 2008 02:05:58 +0000
> "Steven M. Bellovin" <smb%cs.columbia.edu@localhost> wrote:
> 
> > On Sun, 06 Jan 2008 10:56:55 -0500
> > "Jared D. McNeill" <jmcneill%invisible.ca@localhost> wrote:
[..]

> > Diagnostic output I added says that the size of the rbus area
> > was .75GB, starting at 3.25GB.  In other words, it overlaps the
> > entire PCI hole. Is that right?
> > 
> I changed my RBUS_MIN_OPTION to 3GB; that let the EVDO card be
> recognized properly.  The compact flash card worked better -- it
> recognized wdc2 and an atabus controller.  It did not recognize wd2,
> not did it recognize anything when I removed the card.  I tried
> inserting the EVDO card it the same slot; that wasn't noticed.
> However, when I removed the EVDO card, it decided that the CF card had
> been removed.

How will the rbus_machdep.c code work when you have more then 2 or 3GB
of ram?

> Since the differing behavior made me suspect problems with the
> range 3.25-3.5GB, I added code for a new kernel option, RBUS_SIZE.
> It doesn't seem to have helped with the CF card; given that EVDO was
> helped by the change in RBUS_MIN_OPTION, I'm inclined to commit the
> (attached) change, at least until someone who understands the amd64
> architecture can write the correct code.
> 
> Comments?

It strikes me that we have now two rbus_machdep.c files with small
differences. Yes, this is port-amd64, but I first looked in the i386
version and that had some line offsets so it couldn't be that version
which you modified.

Can't we move it to sys/arch/x86/x86 and use some ifdefs?

And it would be nice to have some comments in the source file for new
code what it does.

Bernd