* Arnd Bergmann [off-list ref] [110908 07:23]:

On Wednesday 07 September 2011, Nicolas Pitre wrote:

quoted

On Wed, 7 Sep 2011, Russell King - ARM Linux wrote:

quoted

On Wed, Sep 07, 2011 at 02:36:35PM +0200, Uwe Kleine-K?nig wrote:

quoted

But only if the image doesn't support imx6q, right? Anyhow, I hope
imx6q_map_io isn't called for pre-imx6q SoCs. Ah, and I hope we don't
need to argue here as Russell doesn't like the new DEBUG_LL changes :-)

I have no problem with the Kconfig menu approach or existing approaches
to DEBUG_LL.  What I have an objection to is trying to stuff the
information for it into places which ultimately render the facility
useless for its intended purpose - to permit debugging the really
early assembly code.

That is what it was written for: if we introduce complicated ways to
put behind it, we'll need to come up with a completely new debugging
infrastructure to debug the now buggered debugging infrastructure.

For the record I now agree with Russell.

In order to have early serial output that works across multiple SOCs in 
the same kernel image intended to non developers we'll have to add a 
parallel infrastructure.  Keeping the DEBUG_LL code as simple as 
possible for developers is the way to go (and that might be needed to 
debug that parallel infrastructure).

Yes, agreed. It should not be too hard to provide more CON_BOOT consoles.
For 8250, this can actually be done already using the code from
drivers/tty/serial/8250_early.c with a custom command line, but there
are better ways to do that in a generic way.

Sounds good to me.

Regards,

Tony