[Buildroot] [PATCH] system: add "askfirst shell" as an option for busybox init

Károly Kasza kaszak at gmail.com
Mon Dec 15 11:43:25 UTC 2014


Hi Alexey, list,

On Mon, Dec 15, 2014 at 9:56 AM, Alexey Brodkin <Alexey.Brodkin at synopsys.com
> wrote:
>
> Consider following cases:
>  * Buildroot only builds rootfs that could be used on systems with
>    different default serial ports (ttyS0, ttyS1, ttyAMA3 etc)
>  * Target system has multiple serial ports and in kernel command
>    line users/developers may select different serial ports as
>    debug consoles
>
> In both cases hard-coded with BR2_TARGET_GENERIC_GETTY tty will
> only work for 1 particular serial port.
>
> This change introduces an option to use whatever existing console.
> For example console selected in kernel's command line will be used.
>

I would add another case: when BR is used to build a system without a
dedicated console, but the
SoC can be modified to provide one (like a NAS without a serial port, but
with miniUART inside).
In those cases I've seen OEMs use askfirst in inittab, as it uses less
memory then a getty always waiting.


> I'm not sure if the same thing works for SysVinit so marking it
> dependent on Busybox init.
>
I think it does, but I will test it also when I'll have time.

Anyway, I like this option. Also tested it with my build: x86_64 build and
target platform, uClibc, GCC 4.9.2, kernel 3.18 w/ integrated initrd,
VMware PXE booted, openvmtools included. Works as intended.

Tested-by: Karoly Kasza <kaszak at gmail.com>
Reviewed-by: Karoly Kasza <kaszak at gmail.com>

Best regards,
Karoly
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