[PATCH] ARM: shmobile: alt dts: Drop console= bootargs parameter
Sergei Shtylyov
sergei.shtylyov at cogentembedded.com
Mon Feb 2 14:10:57 PST 2015
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.
>> (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.
>>> Cc: Ulrich Hecht <ulrich.hecht+renesas at gmail.com>
>>> Cc: Geert Uytterhoeven <geert+renesas at glider.be>
>>> Cc: devicetree at vger.kernel.org
>>> Signed-off-by: Simon Horman <horms+renesas at verge.net.au>
>>> ---
>>> 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.
WBR, Sergei
More information about the linux-arm-kernel
mailing list