Re: [PATCH] serial: 8250: Default SERIAL_OF_PLATFORM to SERIAL_8250

[Guenter Roeck <linux@roeck-us.net>]

On Thu, Nov 01, 2018 at 11:26:06AM -0700, Florian Fainelli wrote:
> It is way too easy to miss enabling SERIAL_OF_PLATFORM which would
> result in the inability for the kernel to have a valid console device,
> which can be seen with:
> 
> Warning: unable to open an initial console.
> 
> and then:
> 
> Run /init as init process
> Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000100
> 
> Since SERIAL_OF_PLATFORM already depends on SERIAL_8250 && OF there
> really is no drawback to defaulting this config to the value of
> SERIAL_8250.
> 
> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch results in situations where CONFIG_SERIAL_OF_PLATFORM is now
defined where it was not previously. Example mpc85xx_defconfig. This in
turn results in boot failures for those configurations, with an error
message of

of_serial: probe of e0004500.serial failed with error -22

which wasn't seen before.

Not sure if replacing a potential problem with a real one is really an
improvement.`

Guenter

 ---
>  drivers/tty/serial/8250/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
> index 15c2c5463835..d7737dca0e48 100644
> --- a/drivers/tty/serial/8250/Kconfig
> +++ b/drivers/tty/serial/8250/Kconfig
> @@ -484,6 +484,7 @@ config SERIAL_8250_PXA
>  config SERIAL_OF_PLATFORM
>  	tristate "Devicetree based probing for 8250 ports"
>  	depends on SERIAL_8250 && OF
> +	default SERIAL_8250
>  	help
>  	  This option is used for all 8250 compatible serial ports that
>  	  are probed through devicetree, including Open Firmware based
> -- 
> 2.7.4