Re: Support for serial console on legacy free machines

From: Johannes Erdfelt (
Date: Mon Jul 30 2001 - 23:50:02 EST

On Tue, Jul 31, 2001, Keith Owens <> wrote:
> On Mon, 30 Jul 2001 16:40:31 -0600 (MDT),
> Andreas Dilger <> wrote:
> >What bothers me is that new systems don't have a serial port, and no ISA
> >slots, so there is no hope of getting a "serial console" support without
> >ACPI (which is rather heavyweight AFAIK). USB is far too complex to use
> >for early-boot debugging, so what else is left?
> I briefly discussed this with the USB maintainers at the 2.5 kernel
> developers conference. They thought that a stripped down USB serial
> console was possible, without full USB support. Is that still the
> case?

I think so. Keyboards have a nice feature called boot protocol mode
which is a dumbed down version for BIOS' and the like to use.

What would be needed is a driver for UHCI and OHCI does polling
exclusively, which isn't a big problem and only does control and
interrupt pipes.

I think this can be done with a minimal amount of code. It would
probably be smaller than Linus' original USB driver.


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This archive was generated by hypermail 2b29 : Tue Jul 31 2001 - 21:00:49 EST