[U-Boot] [PATCH] tegra: Specify debugging serial port at boot.

Simon Glass sjg at chromium.org
Thu Mar 22 00:16:44 CET 2012

Hi Wolfgang,

On Wed, Mar 21, 2012 at 4:07 PM, Wolfgang Denk <wd at denx.de> wrote:
> Dear Simon Glass,
> In message <CAPnjgZ0jtSioCq+u2yiaDL6cwV711duWW5uT88mE3oHB-nNmjQ at mail.gmail.com> you wrote:
>> > No.  I do not want to see any PRE_CONSOLE_UART or pre_console_putc()
>> > stuff, because this is bogus.  If you do output to a serial UART port,
>> > this _is_ your console.  Just use it in the standard war.
>> >
>> > I made my mind up: I want to get rid of all this "pre_console" UART
>> > stuff.
>> OK, so revert that commit?
> It hasn't hit mainline yet, or has it?

Yes, it is there, sorry.

>> In that case I have a question. How can we get console output in the
>> event of a panic before console_ready() is called?
> You cannot, by definition. You cannot output anything to the console
> without initializing it before.
> This is why initializing the serial console has always been one of the
> very, very first initialization steps in U-Boot.

So if actually you want a pre-console panic() to be silent then that's fine.

It's a little unfriendly though - so would you be interested in
keeping board_pre_console_putc() around if we could solve this
entirely with code in there? It turns out that Tegra has a setting for
console UART in the hardware parameters that we can access.( I won't
ask you about how to handle a panic() in SPL yet).


> Best regards,
> Wolfgang Denk
> --
> DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
> There are three ways to get something  done:  do  it  yourself,  hire
> someone, or forbid your kids to do it.

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