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Date:      Wed, 30 Aug 2000 16:17:55 -0700
From:      Peter Wemm <peter@netplex.com.au>
To:        John Baldwin <jhb@pike.osd.bsdi.com>
Cc:        alpha@FreeBSD.org
Subject:   Re: Console problems on alpha with -current 
Message-ID:  <200008302317.e7UNHtG96193@netplex.com.au>
In-Reply-To: <200008302227.PAA71069@pike.osd.bsdi.com> 

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John Baldwin wrote:
> Peter Wemm wrote:
> > > This in turn affects the probe order, judging from the dmesg output.
> > > The ultimate effect is this difference:
> > > 
> > >     bad:    sc0: VGA <16 virtual consoles, flags=0x0>
> > >     good:   sc0: VGA <16 virtual consoles, flags=0x200>
> > > 
> > > which I suspect is the reason the console isn't working right.  The
> > > 0x200 flag (actually stored in the "config" field of the softc struct)
> > > is SC_KERNEL_CONSOLE.
> > 
> > *blink*...
> > 
> > It seems that the loader sorts the variables that it passes through to the
> > kernel.   Why this makes a difference is puzzling me somewhat.  However,
> > the Alpha console probe code is totally different to the i386 console probe
> > code.  I suspect that is the root cause of it.
> 
> Mike Smith has suggested that the kenv pointer might not be initialied
> before the console init on the alpha for some reason...

No, the more I think about it, the more I think something like this is
happening:

i386:
console selection is done before any output using the low level console
probe routines.

alpha:
the SRM console is being used until much later, and when sc0 comes up without
vga0 having probed already, then things are breaking.
The difference between static vs. dynamic hints is that loader(8) is sorting
the hints (sc0 comes before vga0) while static hints are preserving the order.

In alpha/conf/GENERIC.hints:
hint.vga.0.at="isa"
hint.sc.0.at="isa"

I'll bet that reversing these two in a static hints kernel will duplicate
the problem that people see with dynamic hints.

Can somebody with a vga console alpha confirm/deny this?

Cheers,
-Peter
--
Peter Wemm - peter@FreeBSD.org; peter@yahoo-inc.com; peter@netplex.com.au
"All of this is for nothing if we don't go to the stars" - JMS/B5



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