On Tue, Jan 11, 2000 at 02:09:04PM -0800, Bill Studenmund wrote:
> On Tue, 11 Jan 2000, Dan Winship wrote:
> > > Our pci code (and I think Linux's also) doesn't support that. I spoke with
> > > Jason, though, and the alpha PCI code has supported that since day 1. So
> > > we can get things working with native (non RTAS) pci support. :-)
> > 
> > Until the next time Apple switches PCI chipsets, at which point,
> > LinuxPPC would already work with it, and we'd need to add more hacks.
> 
> The problem though with not doing a direct support is that we expect to be
> able to do pci config operations well into boot. That doesn't work well
> with quiescing (see below).
> 
> > Plus, adding RTAS support also wins us nvram access and the ability to
> > beep. :)
> 
> Well, the problem is that we're also supposed to shut things down when
> we're running, by quiescing OF. As I understand it, THAT requirement
> shoots down nvram access and beeping. :-(

MacOS has to do the same things that we'll need to do with OF.  MacOS seems
to already shutdown OF within the Trampoline Code[1], which sounds like
a second level booter to me.

The problem I see with RTAS is the lack of documentation for it.  I only 
did a quick search of the Apple Developer Site [2], which only brought up
some glossed over references to it.  What it does bring up makes it sound
like the PPCs version of the Alpha's SRM, which our Alpha port uses and,
IIRC, help keeps the Alpha developers sane.  It wouldn't surprise me if
Apple didn't provide RTAS docs, but someone else does.  Besides, if 
LinuxPPC already has RTAS support, that would make our job easier.

This sounds like the best thing for the macppc port as it both makes it
easy to handle future hardware and may even clear up some of the problems
we've had, like the USB key-repeat bug.

[1] http://developer.apple.com/techpubs/hardware/Developer_Notes/Macintosh_CPUs-G3/PowerBookG3Series_1999/101_.6b.html
[2] http://search03.apple.com/s97is.vts?Action=FilterSearch&ResultTemplate=webx11.hts&ServerKey=Primary&filter=nullflt.hts&SearchPage=http%3A%2F%2Fsearch03.apple.com%2Findex.html&collname=developer&queryText=RTAS&SEARCH.x=26&SEARCH.y=12

jf
-- 
John Franklin
franklin@elfie.org
ICBM: N37 12'54", W80 27'14" Z+2100'