Re: [PATCH v3 2/2] ARM: dts: aspeed: Add device tree for Ampere's Mt. Mitchell BMC

[Quan Nguyen]

On 18/08/2022 19:06, Arnd Bergmann wrote:
> On Thu, Aug 18, 2022 at 9:33 AM Joel Stanley <joel@xxxxxxxxx> wrote:
> > > +
> > > +/ {
> > > +       model = "Ampere Mt.Mitchell BMC";
> > > +       compatible = "ampere,mtmitchell-bmc", "aspeed,ast2600";
> > > +
> > > +       chosen {
> > > +               stdout-path = &uart5;
> >
> > I know you've been told by Arnd and others to remove the default
> > command line here, but without it your device tree fails to produce
> > any output in my tests:
> >
> > qemu-system-arm -M ast2600-evb -nographic -dtb
> > arch/arm/boot/dts/aspeed-bmc-ampere-mtmitchell.dtb -kernel
> > arch/arm/boot/zImage
> >
> > Without a working test, I can't tell the difference between a broken
> > device tree and one that omits the serial device on the command line.
> > Can you work with Arnd to come to a solution here?
>
> If you use qemu as the boot loader, I think the expected way to do
> this is to use the "-append" command line argument along with "-kernel".
>
> Is there any reason for this machine to be special here?

Thanks Arnd for the comment.

I think adding -append could solve the issue.

But as the bootargs still exist in all other 
arch/arm/boot/dts/aspeed-bmc-*.dts should we still keep bootargs for 
this dts?

Thanks,
- Quan