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Subject: Re: [PATCH] powerpc/lpar - defer prefered console setup
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Bastian Blank <waldi@debian.org>
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Date: Tue, 29 Jul 2008 17:43:24 +1000
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On Tue, 2008-07-29 at 09:36 +0200, Bastian Blank wrote:
> On Tue, Jul 29, 2008 at 01:06:18PM +1000, Benjamin Herrenschmidt wrote:
> > On Mon, 2008-07-28 at 20:56 +0200, Bastian Blank wrote:
> > > Hi
> > > 
> > > The powerpc lpar code adds a prefered console at a very early state,
> > > during arch_setup. This runs even before the console setup from the
> > > command line and takes preference.
> > > 
> > > This patch moves the prefered console setup into an arch_initcall which
> > > runs later and allows the specification of the correct console on the
> > > command line. The udbg console remains as boot console.
> > > 
> > Shouldn't it be a console_initcall() ? 
> 
> No. console_initcall is for the initial console setup and runs way long
> before the command line setup. It needs to run after that.

Hrm... we do most of the console discovery from console_initcall for
legacy UARTs. see the code in legacy_serial.c, we just avoid doing
the add_preferred_console() thingy if there's a console= on the command
line :-)

> Yep. Would it be a solution to check this in hvc_vio and hvsi and do the
> calls there? They now that the device is available and the correct
> index. But even then it have to run after the command line. (Or the
> console infrastructure fixed to support more then one device of a type.)

Not sure. The console selection process is just plain weird and I never
really took the time to fully figure it out.

Ben.