[Buildroot] [PATCH] systemd: let getty instead of serial-getty handle /dev/console

On 09/22/2016 08:50 PM, Peter Seiderer wrote:

Hello Floris,

On Wed, 21 Sep 2016 23:47:02 +0200, Floris Bos [off-list ref] wrote:

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On 09/21/2016 10:05 PM, Peter Seiderer wrote:

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Hello *,

On Wed, 21 Sep 2016 09:01:37 +0200, Peter Korsgaard [off-list ref] wrote:

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"Yann" == Yann E MORIN [off-list ref] writes:

   > Floris, All,
   > On 2016-09-09 18:10 +0200, Floris Bos spake thusly:
   >> The serial-getty unit depends on dev-%i.device which does not
   >> seem to be created for /dev/console
   >> Workaround this by letting normal getty unit handle things
   >> if BR2_TARGET_GENERIC_GETTY_PORT is set to 'console'
   >>
   >> Signed-off-by: Floris Bos [off-list ref]

   > I haven't tested that, but I think this is OK just on principle.

   > I just wonder if that behaves correctly when console is a serial line or
   > anything else (e.g. a VT on HDMI, or through a debug channel...)

Yeah, me too. Does anybody know what the difference exactly is between
getty/serial-getty, and when one should be used over the other?

Tested for the rpi3/glibc/systemd case and failed: I get a doubled
(and unusable) ' Welcome to Buildroot/buildroot login:' on serial and
no login on hdmi...

Empty cmdline.txt will give hdmi.

Recall you need "console=serial0,115200 console=tty1" with tty1 last in
cmdline.txt if you want them simultaneous.

Changed cmdline.txt to:

	root=/dev/mmcblk0p2 rootwait console=ttyAMA0,115200 console=tty1

Which gives me two (functional) logins on serial and hdmi.

But I think changing package/rpi-firmware/cmdline.txt unconditional will
break the other Init systems, see commit log from last patch touching
cmdline.txt ([1):

   ...change BR2_TARGET_GENERIC_GETTY_PORT to "console", so it starts a
   getty on the last console= passed to the kernel, ttyAMA0...

Will withdraw my patch then, and wait for someone else to come up with a 
better solution.

I think the one-size-fits all cmdline.txt that listens to both on HDMI 
and serial console by default makes things too complicated anyway.


Yours sincerely,

Floris Bos