On Wed, 25 Jul 2007 15:32:53 +0200 Sébastien Dugué <[email protected]> wrote:
>
> Hi Bjorn,
>
> On Wed, 25 Jul 2007 07:16:44 -0600 Bjorn Helgaas <[email protected]> wrote:
>
> > On Wednesday 25 July 2007 01:45:54 am Sébastien Dugué wrote:
> > > looks like the commit was dropped, nevertheless here is some more info
> > > to try and understand what may be going on so it may benefit the posterity ;-)
> >
> > Thank you very much.
> >
> > Your machine does indeed describe both UARTs in ACPI, and the PNP probe
> > finds them correctly. The only wrinkle is that the PNP probe names the
> > ports in the order they appear in the ACPI namespace, and your firmware
> > has them "backwards":
> >
> > Device (COMB)
> > {
> > Name (_HID, EisaId ("PNP0501"))
> > Name (_DDN, "COM2")
> > Name (_UID, 0x02)
> >
> > Device (COMA)
> > {
> > Name (_HID, EisaId ("PNP0501"))
> > Name (_DDN, "COM1")
> > Name (_UID, 0x01)
>
>
> Yes, that's what I thought was weird in the DSDT, but thought the PnP layer
> would map those devices according to UID or at least DDN. It seems that's
> not the case.
>
> >
> > There's nothing illegal about this, but with the current PNPACPI,
> > it causes the names to be reversed. The blind probe tries 0x3f8
> > first, and names that ttyS0. But the PNP probe, using the namespace
> > order, finds the "COM2" port at 0x2f8 first:
> >
> > 00:0b: ttyS0 at I/O 0x2f8 (irq = 3) is a 16550A
> > 00:0c: ttyS1 at I/O 0x3f8 (irq = 4) is a 16550A
>
> Oh I see, didn't notice this though.
>
> >
> > So I think your serial console would work without "legacy_serial.force"
> > if you used "console=ttyS1" instead of "console=ttyS0". But you
> > shouldn't have to do that, of course.
>
> Will try ttyS1 just to confirm...
>
> Waiting for reboot...
>
> OK boots fine with the serial console fully operational again.
But I also need to change my inittab. At least it confirms the
root cause of the problem.
Sébastien.
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