On Tue, Feb 03, 2015 at 01:10:57AM +0300, Sergei Shtylyov wrote:
> Hello.
>
> On 01/31/2015 07:17 AM, Simon Horman wrote:
>
> >>>Alt is booted from DT, so chosen/stdout-path is
> >>>always used, and we can drop the "console=" parameter from chosen/bootargs.
>
> >>>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.
>
> >> 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.
>From my point of view that is an oversight which I would have
resolved had I ever obtained access to the hardware.
> >>(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)
It looks like my version has some extra patches (the g5df9446 bit).
But I could be reading things wrong.
> >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.
>
> >>>Cc: Ulrich Hecht <ulrich.hecht+renesas@xxxxxxxxx>
> >>>Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> >>>Cc: devicetree@xxxxxxxxxxxxxxx
> >>>Signed-off-by: Simon Horman <horms+renesas@xxxxxxxxxxxx>
> >>>---
> >>> arch/arm/boot/dts/r8a7794-alt.dts | 2 +-
> >>> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> >>>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";
>
> >> 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.
If you are using 'renesas-devel-*' tags (and forward porting) then
you should be in good shape. But if you would like me to verify a particular
tag I'm happy to do so. It is not unheard of for different instances of
the same board behave in different ways.
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