Re: PNPACPI probes serial twice, messes up serial console

[Bjorn Helgaas <bjorn.helgaas@hp.com>]

On Wednesday 21 March 2007 10:37, Russell King wrote:
> On Wed, Mar 21, 2007 at 10:35:38AM -0600, Bjorn Helgaas wrote:
> > On Tuesday 20 March 2007 08:32, Bjorn Helgaas wrote:
> > > On Tuesday 20 March 2007 00:46, Keith Owens wrote:
> > > > Booting with 'console=tty console=ttyS0,9600'.  The serial console on
> > > > ttyS0 (0x3f8, irq 4) is probed twice, once from serial8250_init() and
> > > > again from serial_pnp_probe().
> > > 
> > > I played with this last summer, but was too timid to finish it
> > > and post it.  My plan was to remove the legacy SERIAL_PORT_DFNS,
> > > make platform devices for them, and only register the platform
> > > devices in the absence of PNP.
> > > 
> > > My motivation at the time was to prevent 8250 from claiming IRDA
> > > devices that happened to live at legacy UART addresses.  I also
> > > wanted to make IRDA (smsc-ircc2 in my case) smart enough to use
> > > PNP to locate its devices, since 8250 would no longer claim them.
> > > 
> > > Here's the dusty patch (against 2.6.18-rc1-mm2).  If it seems
> > > like a reasonable thing to do, I can update it, polish it up,
> > > add a changelog, and post it.
> > 
> > Keith, does this patch help?  Russell didn't complain about it, so
> > if it fixes your problem, maybe we could put it in -mm and see if
> > it breaks anything else.
> 
> Yes I did.

Sorry.  What I should have said was "Russell gave constructive
feedback for a minor improvement, but didn't complain about the
overall approach of converting to platform devices, so if the
patch solves your (Keith's) problem, I'll incorporate Russell's
feedback and send an updated patch to Andrew."

Bjorn