Re: Early console confusion

From: H. Peter Anvin
Date: Wed Sep 22 2010 - 12:54:31 EST


On 09/22/2010 09:44 AM, Bjorn Helgaas wrote:

If we don't like "uart8250,io,0x3f8" (which I agree is awfully clunky),
we could easily add something like "console=com1" which encapsulated
the well-defined PC concept.

console=ttyS0 ... already works fine.

It would be similar to "earlyprintk=ttyS0",
and if it could be made *enough* like it, maybe "earlyprintk=ttyS0"
could be dropped.

I also see the recent "earlyprintk=hsu" patch from Feng Tang, and I
wonder whether that could be recast in the "console=hsu" style. Like
"com1", "hsu" is apparently enough to specifically identify a device.

I think it's nicer to extend "console=" in ways that allow early
devices, because then users don't have to mess with both "console="
and "earlyprintk=". The 8250_early driver has a reasonable model
of switching from the early device to the real one automatically,
so maybe something like this is all we would need:

console= is supported multiple times, and enabling console= shouldn't necessarily enable earlyprintk...

But yes, it's ugly and we have bass-ackwards compatibility problem...

-hpa
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