Re: [RFC] arm64: Early printk support for virtio-mmio console devices.

[Catalin Marinas <catalin.marinas@arm.com>]

On Fri, Apr 19, 2013 at 05:14:36PM +0100, Peter Maydell wrote:
> On 19 April 2013 17:12, Catalin Marinas <catalin.marinas@arm.com> wrote:
> > On Fri, Apr 19, 2013 at 11:05:47AM +0100, Peter Maydell wrote:
> >> Please make the kernel pick the device out of the device tree
> >> blob. The whole point of device tree is that it's how to tell
> >> the kernel where things live -- making kvmtool/QEMU and/or the
> >> user also have to mess with the kernel command line is awkward
> >> and annoying.
> >
> > For a normal console device, it indeed needs to get it from the DT. For
> > early console, you want it earlier than DT parsing so we pass it on the
> > kernel command line via the earlyprintk= parameter.
> 
> You should fix your DT handling code so you can get at the info
> when you need it rather than pushing the problem into bootloaders
> and QEMU, please. DT is your data structure so feel free to
> (re)design it so relevant information can be accessed early
> if that's useful.

earlyprintk is used for debugging early problems, like DT parsing. You
don't have to use it unless you are debugging something. Without
earlyprintk you just get a normal console during boot, based on the DT
description.

-- 
Catalin