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Date: Tue, 31 Jul 2001 10:10:28 -0600
From: Khalid Aziz <khalid@fc.hp.com>
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To: Stuart MacDonald <stuartm@connecttech.com>
Cc: Linux kernel development list <linux-kernel@vger.kernel.org>
Subject: Re: Support for serial console on legacy free machines
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Stuart MacDonald wrote:
> 
> It seems like pci consoles won't work, now that I think about it. The
> console driver gets an index, which I'm going to assume works thusly:
> lilo console=ttyS1 ends up passing 1 as the index. That index is used
> to pick a serial port out of the array of serial ports that the driver
> knows about. If console init happens early, and serial driver init happens
> late (it would be dependent on pci init) then only hard coded ports
> would work. Those are defined in asm/serial.h, and for i386 include the
> standard ports, and a number of isa ports from various board manufacturers.
> 
> Using one of our pci ports would require knowledge of its io address,
> which wouldn't be available until the pci subsystem had inited. Perhaps
> that could be changed to allow pci based consoles?
> 

That is precisely the problem with trying to use a PCI serial port as
console. It is not trivial to move the PCI initialization earlier in the
boot sequence.

-- 
Khalid

====================================================================
Khalid Aziz                              Linux Systems Operation R&D
(970)898-9214                                        Hewlett-Packard
khalid@fc.hp.com                                    Fort Collins, CO
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