Hi Arnd, On Wed, 11 Mar 2020 at 22:31, Arnd Bergmann <arnd@xxxxxxxx> wrote: > > On Wed, Mar 11, 2020 at 12:21 PM Chunyan Zhang <zhang.lyra@xxxxxxxxx> wrote: > > > > > diff --git a/arch/arm64/boot/dts/sprd/sp9863a-1h10.dts b/arch/arm64/boot/dts/sprd/sp9863a-1h10.dts > > index 2047f7a74265..510f65f4d8b8 100644 > > --- a/arch/arm64/boot/dts/sprd/sp9863a-1h10.dts > > +++ b/arch/arm64/boot/dts/sprd/sp9863a-1h10.dts > > @@ -28,7 +28,7 @@ > > > > chosen { > > stdout-path = "serial1:115200n8"; > > - bootargs = "earlycon"; > > + bootargs = "earlycon console=ttyS1"; > > }; > > }; > > Hi Chunyan, > > I would expect that you need to either specify the stdout-path, or the console= > kernel parameter, but not both. > Ok, now I know how to fix the problem without adding 'console=' :) of_console_check() [1] can tell if a given port is the console by reading 'stdout-path'. I will address this issue in serial driver. Thanks for your reminder, Chunyan [1] https://elixir.bootlin.com/linux/v5.6-rc5/source/drivers/of/base.c#L2135 > If earlycon was used, shouldn't the driver know which port is the console? > > Arnd