From: Russell King <rmk+lkml@arm.linux.org.uk>
Date: Wed, 4 Apr 2007 10:00:16 +0100
The platform should use whatever is appropriate, and matches
firmware/bios/whatever conventions, to determine this stuff.
On Sparc you get an openfirmware environment variable called
"output-device" that can point to a framebuffer or serial
console device.
The user can override this on the kernel command line, of course, and
what they ask for will get translated properly.
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