Re: commit 7e92b4fc34 - x86, serial: convert legacy COM ports to platform devices - broke my serial console

From: Yinghai Lu
Date: Wed Jul 25 2007 - 12:45:38 EST


On 7/25/07, Bjorn Helgaas <bjorn.helgaas@xxxxxx> wrote:
On Wednesday 25 July 2007 09:57:47 am Yinghai Lu wrote:
> On 7/25/07, Bjorn Helgaas <bjorn.helgaas@xxxxxx> wrote:
> > On Tuesday 24 July 2007 10:27:26 pm Yinghai Lu wrote:
> > > or we can make legacy_serial.force=1 is default at this point.
> >
> > At which point? We already do the legacy probe if there are no
> > PNP devices. Do you mean we should also do the legacy probe if
> > there are PNP devices, but no serial devices were found? That
> > might be reasonable to do, but wouldn't have prevented the problem
> > on Sebastien's machine, because his machine *does* have PNP UARTs.
>
> but still could have problem. if the system does not have any uart,
> and So we can not find that in DSDT...and we add legacy again...that
> is not right.

I'm sorry, I don't understand what you're saying.

The behavior with my patch is: If we have PNPBIOS or ACPI, and it
does not describe any UARTs, we assume the box has no UARTs. If we
don't have PNPBIOS or ACPI, we blindly probe for legacy UARTs.

What behavior are you suggesting?

*** If we have PNPBIOS or ACPI, and it does describe any UARTs, we
assume the box has no other legacy UARTs.
*** If we have PNPBIOS or ACPI, and it does not describe any UARTs,
we blindly probe for legacy UARTs. ----------in case old box DSDT
doesn't have PNP0501 there in DSDT.
If we don't have PNPBIOS or ACPI, we blindly probe for legacy UARTs.

YH
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