[U-Boot] [PATCH 2/2] serial: Make nulldev a serial device

[Joe Hershberger]

Hi Marek,

On Fri, Nov 2, 2012 at 8:37 PM, Marek Vasut <marex at denx.de> wrote:
> Dear Joe Hershberger,
>
>> This allows the default console to be specified as the nulldev.  This is
>> specifically helpful when the real serial console's init() cannot run
>> early in the boot process.  When the init can be run, then the console
>> can be switched to the real device using the std* env vars.
>>
>> Signed-off-by: Joe Hershberger <joe.hershberger at ni.com>
>
>
> Isn't it actually better to have null stdio device? Some systems might not even
> use serial port (and so null serial will be useless on these systems)!

As I described in my commit log, this is for the case where the serial
and console init must not touch the hardware, (since it doesn't exist
yet if it's in an FPGA or on a PCI or USB connection).  Making the
default serial port be the nulldev avoids this issue.

As for systems with no real serial port, there can still be the
nulldev serial device... or not.  Why is that a problem?

-Joe