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SubjectRe: Wait for console to become available, v3.2
Date
On Monday 20 April 2009, Ingo Molnar wrote:
> The proper approach would be to use one of the async_synchronize*()
> facilities in kernel/async.c to properly order the opening of the
> console with device init.

Stepping back a moment from "how" to make sure "what" is agreed on.

I think I see three scenarios here:

- Classic PC or server, where there's a meaningful console;

- Deeply embedded systems, where there isn't;

- Development stages of "deeply embedded", where there *may* be one.

If that's correct, then async_synchronize() isn't a full answer...

I think a fair number of cases can be papered over with a serial
console with no hardware flow control, which isn't hooked up to
anything. Maybe the board needs a test/development jig to get one;
without it, the "console" bits spill out into the aether. Linux
can dump bits to ttyS0, which will act like /dev/null.

But the problem case here seems to be one where such un-hooked-up
serial ports are not realistic options. Which is why the regression
in USB console functionality has been troublesome.


Is that correct?

- Dave


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