Hello.

On 01/31/2015 07:17 AM, Simon Horman wrote:

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Alt is booted from DT, so chosen/stdout-path is
always used, and we can drop the "console=" parameter from chosen/bootargs.

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This change has a side-effect of changing the console speed from 38400
to 115200. This is intentional as 115200 is consistently used on
all other shmobile boards.

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    I'd say it's not very practical to change the console's baud rate from
U-Boot's default

It is consistent with the handling of all other boards with
renesas SoCs that are present in mainline.

    Well, not quite: Henninger/Porter is still using 38400.

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(AFAIR changing baud rate in U-Boot didn't work)...

    That was a recollection from the other board though, I haven't yet tried 
to do it on the SILK board (and I'm unable to currently as the power supply 
seems dead).

Perhaps that relates to the version of built of uboot.
On the board I have access to I see:

ver=U-Boot 2013.01.01-g5df9446 (Oct 01 2014 - 14:59:23)

U-Boot 2013.01.01 (Oct 17 2014 - 20:59:18)

And the following setting altered the baud rate of u-boot (IIRC).

baudrate=115200

    I was going to try that but the board just didn't power up.

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Cc: Ulrich Hecht <redacted>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: devicetree at vger.kernel.org
Signed-off-by: Simon Horman <redacted>
---
  arch/arm/boot/dts/r8a7794-alt.dts | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

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diff --git a/arch/arm/boot/dts/r8a7794-alt.dts b/arch/arm/boot/dts/r8a7794-alt.dts
index 8aec512..f2cf757 100644
--- a/arch/arm/boot/dts/r8a7794-alt.dts
+++ b/arch/arm/boot/dts/r8a7794-alt.dts

@@ -20,7 +20,7 @@
  	};

  	chosen {
-		bootargs = "console=ttySC0,38400 ignore_loglevel rw root=/dev/nfs ip=dhcp";
+		bootargs = "ignore_loglevel rw root=/dev/nfs ip=dhcp";

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    Hm, does this even work as intended? I've tried to boot another R8A7794
based board and I couldn't get any output with alike command line. Booting
with 'earlyprintk=serial' has shown that tty0 was enabled as a console which
is not what we wanted.

If you are backporting this change then I believe it has some dependencies
that I can follow up on if it is useful to you.

    Contrariwise, I'm forward-porting.

If you are using mainline (e.g. next or renesas-next) then yes,
it works. I have tested it numerous times since the patch was merged.

    I'm traditionally using the 'renesas-devel-*' tags.

WBR, Sergei