ARC no console output (was Re: [PATCH 1/2] init/console: Use ttynull as a fallback when there is no console)

[Petr Mladek]

On Thu 2021-01-07 08:43:16, Vineet Gupta wrote:
> Hi John,
> 
> On 1/7/21 1:02 AM, John Ogness wrote:
> > Hi Vineet,
> > 
> > On 2021-01-06, Vineet Gupta <vgupta at synopsys.com> wrote:
> > > This breaks ARC booting (no output on console).
> > 
> > Could you provide the kernel boot arguments that you use? This series is
> > partly about addressing users that have used boot arguments that are
> > technically incorrect (even if had worked). Seeing the boot arguments of
> > users that are not experiencing problems may help to reveal some of the
> > unusual console usages until now.
> 
> 
> Kernel command line: earlycon=uart8250,mmio32,0xf0005000,115200n8
> console=ttyS0,115200n8 debug print-fatal-signals=1

This is strange, the problematic patch should use ttynull
only as a fallback. It should not be used when a particular console
is defined on the command line.

The only explanation would be that ttyS0 gets registered too late
and ttynull is added as a fallback in the meantime.

Anyway, I propose the revert the problematic patch for 5.11-rc3,
see
https://lore.kernel.org/lkml/20210107164400.17904-2-pmladek@suse.com/
This mystery is a good reason to avoid bigger changes at this stage.

Best Regards,
Petr